On again? Trump says still chance of June 12 North Korea summit

U.S. President Donald Trump leaves the White House for a trip to Annapolis, Maryland, in Washington, U.S. May 25, 2018. REUTERS/Carlos Barria

By Roberta Rampton and Christine Kim

WASHINGTON/SEOUL (Reuters) – U.S. President Donald Trump dangled the possibility on Friday that a June 12 summit with North Korea’s leader Kim Jong Un, could still take place, just a day after he canceled the meeting citing Pyongyang’s “open hostility.”

Trump indicated the summit could be salvaged after welcoming a conciliatory statement from North Korea saying it remained open to talks.

“It was a very nice statement they put out,” Trump said as he left the White House to deliver a commencement address at the U.S. Naval Academy. “We’ll see what happens – it could even be the 12th.

“We’re talking to them now. They very much want to do it. We’d like to do it.”

An official form North Korea's Nuclear Weapons Institute talks to reporters during the dismantlement process in Punggye-ri, North Hamgyong Province, North Korea May 24, 2018. Picture taken May 24, 2018 News1/Pool via REUTERS

An official form North Korea’s Nuclear Weapons Institute talks to reporters during the dismantlement process in Punggye-ri, North Hamgyong Province, North Korea May 24, 2018. Picture taken May 24, 2018 News1/Pool via REUTERS

Earlier on Twitter, Trump had noted “very good news to receive the warm and productive statement from North Korea.”

After decades of tension on the Korean Peninsula and antagonism with the United States over Pyongyang’s nuclear weapons program, Kim and Trump agreed to what would be the first meeting between a serving U.S. president and a North Korean leader. The plan followed months of war threats and insults traded between the leaders, as well as advances in North Korean missiles capable of reaching the United States.

Trump scrapped the meeting on Thursday after repeated threats by North Korea to pull out of the summit in Singapore over what it saw as confrontational remarks by U.S. officials. Trump cited North Korean hostility in canceling the summit.

In Pyongyang, North Korean Vice Foreign Minister Kim Kye Gwan said North Korea’s criticisms of certain U.S. officials had been a reaction to American rhetoric and that the current antagonism showed “the urgent necessity” for the summit.

“His sudden and unilateral announcement to cancel the summit is something unexpected to us and we cannot but feel great regret for it,” Kim Kye Gwan said of Trump in a statement on state media.

He said North Korea remained open to resolving issues with Washington “regardless of ways, at any time.”

Trump’s latest about-face sent officials scrambling in Washington. U.S. Defense Secretary Jim Mattis told reporters diplomats were “still at work” and said Trump had just sent a note out on the summit, which could be back on “if our diplomats can pull it off.”

North Korea had sharply criticized suggestions by Trump’s national security adviser, John Bolton, and Vice President Mike Pence that it could share the fate of Libya if it did not swiftly surrender its nuclear arsenal. Libyan leader Muammar Gaddafi was deposed and killed by NATO-backed militants after halting his nascent nuclear program.

Kim Kye Gwan said North Korea appreciated Trump having made the bold decision to work toward a summit.

“We even inwardly hoped that what is called ‘Trump formula’ would help clear both sides of their worries and comply with the requirements of our side and would be a wise way of substantial effect for settling the issue,” he said.

Trump had initially sought to placate North Korea, saying he was not pursuing the “Libya model” in getting the North to abandon its nuclear weapons program. White House press secretary Sarah Huckabee Sanders said: “This is the President Trump model. He’s going to run this the way he sees fit.”

A command post of Punggye-ri nuclear test ground is blown up during the dismantlement process in Punggye-ri, North Hamgyong Province, North Korea May 24, 2018. Picture taken May 24, 2018. News1/Pool via REUTERS

A command post of Punggye-ri nuclear test ground is blown up during the dismantlement process in Punggye-ri, North Hamgyong Province, North Korea May 24, 2018. Picture taken May 24, 2018. News1/Pool via REUTERS


U.S. regional allies Japan and South Korea, as well as North Korea’s main ally, China, urged the two countries to salvage the summit on Friday.

At an economic forum in St. Petersburg, Chinese Vice President Wang Qishan said such a summit was necessary to ensure security on the Korean peninsula, which touched on China’s core interests.

Japanese Prime Minister Shinzo Abe, at the same forum, regretted the cancellation of the summit and said the world should keep doing its bit to make it happen.

In Seoul, South Korean President Moon Jae-in, who had urged Trump at a White House meeting on Tuesday not to let a rare opportunity slip away, said on Thursday he was “perplexed” by the cancellation.

South Korea also would continue efforts to improve ties with the North, the presidential office said after Moon’s top security advisers met for the second time on Friday.

Some analysts worried that canceling the summit could prompt a resumption in hostilities, including renewed shorter-range missile tests or stepped-up cyber attacks by Pyongyang and increased sanctions or deployment of new military assets by Washington.

In his letter, Trump warned Kim of the United States’ greater nuclear might, reminiscent of the president’s tweet last year asserting that he had a “much bigger” nuclear button than Kim.

While the Trump administration had insisted on North Korea’s complete, verifiable and irreversible dismantling of its nuclear program, Pyongyang had always couched its language in terms of denuclearization of the Korean peninsula.

It has said in previous, failed talks that it could consider giving up its arsenal if the United States provided security guarantees by removing its troops from South Korea and withdrawing its so-called nuclear umbrella of deterrence from South Korea and Japan.

Before Trump scrapped the meeting on Thursday, North Korea said it had completely dismantled its Punggye-ri nuclear test facility “to ensure the transparency of discontinuance” of nuclear testing.


(Additional reporting by Doina Chiacu, Idrees Ali, David Brunnstrom and Matt Spetalnick in WASHINGTON, Christian Lowe, Denis Pinchuk and Katya Golubkova in St Petersburg; Writing by So Young Kim and Doina Chiacu; Editing by Bill Trott)

Trump cancels summit with North Korea scheduled for next month

FILE PHOTO: A combination photo shows U.S. President Donald Trump and North Korean leader Kim Jong Un (R) in Washignton, DC, U.S. May 17, 2018 and in Panmunjom, South Korea, April 27, 2018 respectively. REUTERS/Kevin Lamarque and Korea Summit Press Pool/File Photos

By David Brunnstrom and Matt Spetalnick

WASHINGTON (Reuters) – U.S. President Donald Trump on Thursday called off a planned historic summit with North Korean leader Kim Jong Un, even after North Korea followed through on a pledge to blow up tunnels at its nuclear test site.

Referring to a scheduled June 12 meeting with Kim in Singapore, Trump said in a letter to the North Korean leader: “Sadly, based on the tremendous anger and open hostility displayed in your most recent statement, I feel it would be inappropriate, at this time, to have this long- planned meeting.”

Trump called it “a missed opportunity” and said he still hoped to meet Kim someday.

The North Korean mission to the United Nations did not immediately respond to a request for comment on Trump’s cancellation of the summit.

U.S. stocks dropped sharply on the news, with the benchmark S&P 500 Index falling more than half a percent in about 10 minutes. Investors turned to U.S. Treasury debt as a safe alternative, driving the yield on the 10-year note, which moves inversely to its price, down to a 10-day low and back below the psychologically important 3 percent level.

The U.S. dollar also weakened broadly, particularly against the Japanese yen, which climbed to a two-week high against the greenback.

“Please let this letter serve to represent that the Singapore summit, for the good of both parties, but to the detriment of the world, will not take place,” Trump wrote.

“You talk about your nuclear capabilities, but ours are so massive and powerful that I pray to God that they will never have to be used,” he said.

Earlier on Thursday, North Korea repeated a threat to pull out of the summit with Trump next month and warned it was prepared for a nuclear showdown with Washington if necessary.


North Korea’s pursuit of nuclear weapons has been a source of tension on the Korean peninsula for decades, as well as antagonism with Washington. The rhetoric reached new heights under Trump as he mocked Kim as “little rocket man” and in address at the United Nations threatened to “totally destroy” North Korea if necessary. Kim had called Trump mentally deranged and threatened to “tame” him with fire.

Kim rarely leaves North Korea and his willingness to meet and Trump’s acceptance sparked hope but it had faded in recent days.

In a statement released by North Korean media, Vice Foreign Minister Choe Son Hui had called U.S. Vice President Mike Pence a “political dummy” for comparing North Korea – a “nuclear weapons state” – to Libya, where Muammar Gaddafi gave up his unfinished nuclear development program, only to be later killed by NATO-backed fighters.

“Whether the U.S. will meet us at a meeting room or encounter us at nuclear-to-nuclear showdown is entirely dependent upon the decision and behavior of the United States,” Choe said.

A small group of international media selected by North Korea witnessed the demolition of tunnels at the Punggye-ri site on Thursday, which Pyongyang says is proof of its commitment to end nuclear testing.

The apparent destruction of what North Korea says is its only nuclear test site has been widely welcomed as a positive, if largely symbolic, step toward resolving tension over its weapons. North Korean leader Kim has declared his nuclear force complete, amid speculation the site was obsolete anyway.

Cancellation of what would have been the first ever summit between a serving U.S president and a North Korean leader denies Trump what supporters hoped could have been the biggest diplomatic achievement of his presidency, and one worthy of a Nobel Prize.

“I felt a wonderful dialogue was building between you and me, and ultimately it is only that dialogue that matters,” Trump said in his letter to Kim. “Some day, I look very much forward to meeting you.”

(Reporting by Joyce Lee; additional reporting by Ben Blanchard in Beijing and Hyonhee Shin in Seoul; Writing by Josh Smith and Doina Chiacu; Editing by Robert Birsel and Bill Trott)

North Korea ‘declines’ South Korea media for nuclear site event; China urges ‘stability’

FILE PHOTO: North Korean leader Kim Jong Un and South Korean President Moon Jae-in deliver a statement at the truce village of Panmunjom inside the demilitarized zone separating the two Koreas, South Korea, April 27, 2018. Korea Summit Press Pool/Pool via Reuters

By Heekyong Yang

SEOUL (Reuters) – North Korea has declined to accept a list of South Korean journalists hoping to observe the closure of its nuclear test site, South Korea said on Friday, raising new questions about the North’s commitment to reducing tension.

North Korea had invited a limited number of journalists from South Korea and other countries to witness what it said will be the closing of its only nuclear weapons test site at Punggye-ri next week.

The North Korean offer to scrap the test site has been seen as major concession in months of easing tension between it, on the one hand, and South Korea and the United States on the other.

But the remarkable progress appears to have been checked in recent days with North Korea raising doubts about an unprecedented June 12 summit in Singapore between leader Kim Jong Un and U.S. President Donald Trump, and calling off talks with the South.

The South Korean Unification Ministry, which handles dealings with the North, said on Friday North Korea had “declined to accept” the list of journalists submitted by the South for the test site dismantling.

The ministry did not elaborate but the North Korean decision is likely to raise doubts about its plan for the test site.

Trump on Thursday sought to placate North Korea after it threatened to call off the June summit, saying Kim’s security would be guaranteed in any deal and his country would not suffer the fate of Muammar Gaddafi’s Libya, unless that could not be reached.

North Korea had said on Wednesday it might not attend the Singapore summit if the United States continued to demand it unilaterally abandon its nuclear arsenal, which it has developed in defiance of U.N. Security Council resolutions to counter perceived U.S. hostility.

On Thursday, North Korea’s chief negotiator called South Korea “ignorant and incompetent” and denounced U.S.-South Korean air combat drills and threatened to halt all talks with the South.

Trump, in rambling remarks in the White House’s Oval Office, said as far as he knew the summit was still on track, but that the North Korean leader was possibly being influenced by Beijing.

But he also stressed that North Korea would have to abandon its nuclear weapons and warned that if no deal was reached, North Korea could be “decimated” like Libya or Iraq.


China, responding to U.S. President Donald Trump suggestion that Beijing may be influencing North Korea’s new hardline stance, said on Friday it stands for stability and peace on the Korean peninsula and for settlement of confrontation over its development of weapons through talks.

Chinese foreign ministry spokesman Lu Kang, asked about Trump’s comments, said China’s position had not changed and he reiterated that it supported the goal of denuclearisation on the Korean peninsula.

“We are consistently supporting all relevant parties in resolving the peninsula issue through political consultations and peaceful means,” Lu told a regular briefing.

Kim has made two visits to China recently for talks with President Xi Jinping, including a secretive train trip to Beijing in late March, his first known visit outside North Korea since coming to power.

He flew to the port city of Dalian this month.

Both times, Kim’s encounters with Xi were cast by Chinese state media as friendly. They included beachside strolls and Xi saying that previous generations of North Korean and Chinese leaders had visited each other as often as relatives.

The warmth between the two leaders marks a sharp reversal in what had been months of frosty ties, as China ratcheted up sanction pressure on North Korea in response to its relentless missiles and nuclear tests last year.

China is North Korea’s largest trading partner and considers it an important security buffer against the U.S. military presence in region.

What had seemed until this week to be rapidly warming ties between North Korea, on the one hand, and South Korea and the United States on the other, had fueled fears in Beijing that it might be left out of a new deal on the peninsula, according to analysts.

(Additonal reporting by Micheal Martina, in BEIJING; Writing by Christian Shepherd; Editing by Josh Smith, Robert Birsel)

North Korea is dismantling its nuclear site, but is it abandoning its arsenal or hiding evidence?

A satellite photo of the Punggye-Ri nuclear test site in North Korea May 14, 2018. Planet Labs Inc/Handout via REUTERS

By Josh Smith

SEOUL (Reuters) – Satellite imagery shows North Korea dismantling facilities at its nuclear test site, but experts say the images can’t reveal whether it is the first step toward full denuclearization, or an attempt to cloak nuclear capabilities from outside observers.

North Korea’s intentions were thrown further into doubt on Wednesday, when it abruptly announced it may “reconsider” meeting with U.S. President Donald Trump in June if the United States continues to insist on unilateral denuclearization.

Commercial satellite imagery – including photos taken by Planet Labs as recently as May 14 – show North Korea removing some structures around its nuclear test site at Punggye-ri, experts say.

“So far it looks like the surface-level support structures are being dismantled,” said Scott LaFoy, an open source imagery analyst. “This would be consistent with the site being closed, as you need engineers and working teams on-site to prepare and maintain the site.”

Among the facilities that appear to have been razed are an engineering office, as well as buildings housing the air compressor used to pump air into the tunnels where the bombs were detonated, said non-proliferation expert Frank Pabian.

“This is entirely in keeping with the official North Korean news report that ‘technical measures’ associated with the shutdown were underway,” Pabian said.

North Korea has said it plans to use explosives to collapse the tunnels; “completely” block up the tunnel entrances; and remove observation facilities, research institutes and guard structures.

A limited number of foreign media have been invited to view the ceremonial closure of the site, but so far no international inspectors, leading some experts to suspect that North Korea is seeking to hide details of its nuclear capabilities.

“North Korea might seem like they’re being generous in holding this event, but this is the actual testing ground we’re talking about here – The smoking gun,” said Suh Kune-yull, professor of nuclear energy system engineering at Seoul National University. “It seems like they’re trying to erase any evidence of the nuclear capabilities they have.”


In a statement on Wednesday, North Korea’s first vice minister of foreign affairs Kim Kye Gwan sharply criticized American officials – especially national security adviser John Bolton – for suggesting that Libya could be a template for denuclearizing North Korea.

Bolton has proposed Trump and North Korean leader Kim Jong Un make a deal similar to the one that led to components of Libya’s nuclear program being shipped to the United States in 2004.

In 2011, Libyan leader Muammar Gaddafi was captured and killed by rebel forces backed by a NATO air campaign.

While the technical aspects of a North Korea deal could mirror some aspects of the Libya effort, Pyongyang has a much more advanced weapons program and Gaddafi’s fate is not encouraging, Andreas Persbo, the executive director of VERTIC, a London think tank that focuses on disarmament verification and implementation, said in a recent interview.

“Libya is a horrible example to make out of that perspective because of course the North Koreans have their own teams advising Kim Jong Un on what this meant, and they will highlight the fact that this is not a good solution for North Korea,” he said.

North Korea appears instead to be proposing a longer-term general commitment to “denuclearization of the Korean peninsula,” which could take years even under the best circumstances, experts say.

LaFoy said North Korea’s actions so far are “not necessarily nefarious,” but that it does raise some “red flags” about complete permanent denuclearization.

“That imagery tells us the site appears to be in the process of decommissioning,” he said. “But we can’t yet tell if it is going to be closed for years or something that can ultimately be reversed in a few weeks or months.”

(GRAPHIC: Nuclear North Korea – https://tmsnrt.rs/2Kql12i)

(Additional reporting by Christine Kim in SEOUL and Malcolm Foster in TOKYO. Editing by Lincoln Feast.)

Safety, verification questions hang over North Korea’s plan to close nuclear site

FILE PHOTO: North Korean leader Kim Jong Un provides guidance with Ri Hong Sop (3rd L) and Hong Sung Mu (L) on a nuclear weapons program in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang September 3, 2017. KCNA via REUTERS/File Photo

By Josh Smith and David Brunnstrom

SEOUL/WASHINGTON (Reuters) – Shutting down North Korea’s nuclear test site is trickier than it might seem.

A botched tunnel collapse could spread radioactive debris. Nuclear material might be buried, but accessible enough to be dug up and reused in a weapon. And even if all the testing tunnels are destroyed, North Korean engineers could simply dig a new one if they want to conduct another nuclear test.

Disarmament experts have raised many such scenarios after North Korea said over the weekend that it would use explosives to collapse the tunnels of its Punggye-ri nuclear test site next week.

Pyongyang has publicly invited international media to witness the destruction, but not technical inspectors, leaving disarmament experts and nuclear scientists wondering how effective the plan is – and whether it will be safe.

Recent reports indicate that some areas of the Punggye-ri test site have become unstable after the latest and largest nuclear test in September.

More explosions would be unnecessarily risky, but there are steps North Korea could take to make the shutdown more credible and safe, said Suh Kune-yull, professor of nuclear energy systems engineering at Seoul National University.

“Blowing up isn’t the most ideal way,” Suh said. “It might be less dramatic than an explosion, but filling the tunnel up with concrete, or sand or gravel would be best.”

There is still a considerable amount of radiation being detected at one of the tunnel complexes where most of North Korea’s nuclear tests have taken place, including the latest test of what North Korea said was a fusion bomb, he said.

But underground nuclear test tunnels and shafts are typically designed to be sealed by the nuclear bomb’s blast wave before radioactive material can escape. Some experts noted that North Korea over the course of its six nuclear tests probably learned how to prevent radiation leaks.

“If it’s done well, there is no risk of radiation being released. But the question is, are these tunnels being sealed in a way that they couldn’t again be used?” said Jon Wolfsthal, the director of the Nuclear Crisis Group and a former senior arms control official at the U.S. National Security Council.

“The only risk I see is that we will take the destruction of a couple of tunnels as a physical barrier to the resumption of testing in the future.”


North Korea’s shutting down its test site could be an effort to mirror other nuclear powers that have ended testing, but hung onto their weapons, analysts say.

Suh said beyond closing tunnels and knocking down buildings, the entire Punggye-ri site will need to be secured to prevent the North Koreans or profiteers from digging up nuclear material that could be reused in weapons or sold on the black market.

Previous efforts to close underground nuclear test sites have sometimes been messy, drawn-out affairs, he said.

In 1999, the United States provided $800,000 to pay for a blast equivalent to 100 tons of dynamite to collapse a tunnel at a former Soviet test site in Kazakhstan.

Known as “Plutonium Mountain,” the Soviet Union’s Semipalatinsk Test Site covered an area roughly the size of Belgium and was the scene of 456 nuclear tests during the Cold War, including at least 340 underground blasts.

Cleaning up and securing that site took 17 years and $150 million, according to a report by Harvard’s Belfer Centre.

France, which performed 13 underground nuclear tests in the Sahara Desert in the 1960s, says it “shut down and dismantled its nuclear test facilities,” and a 2005 report by the International Atomic Energy Agency concluded that most of the sites in Algeria show “little residual radioactive material.”

But local people and Algeria’s government said the tests – including the 1962 “Beryl Incident” when radioactive rock and dust escaped from an underground nuclear blast – left a legacy of environmental devastation and health problems that last today.

China, Pakistan, India are also known to have conducted underground nuclear tests. South Africa – which dismantled its entire nascent nuclear weapons program in 1989 – closed down its underground shafts without conducting a test.

The United States, meanwhile, detonated at least 828 nuclear bombs underground at its Nevada Test Site.

The site remains open, although no U.S. nuclear tests have been carried out since 1992.


Nuclear experts say the shutdown plan is at least an encouraging political gesture ahead of talks with the United States in June.

But they caution it is not necessarily the first step of the “complete, verifiable and irreversible dismantlement” of the nuclear program the United States has sought.

The U.S. State Department did not give a specific response when asked whether the United States had asked to send observers to the dismantling of the site or for international monitors to be present.

A spokesman said: “A permanent and irreversible closure that can be inspected and fully accounted for is a key step in the denuclearization of (North Korea). We look forward to learning additional details.”

China – which borders North Korea only about 100 kilometers (62 miles) from Punggye-ri – has not publicly said whether it would help dismantle the site or monitor the process.

“To my understanding, the North Korean side has not raised this kind of request to the Chinese side,” a spokesman for China’s foreign ministry said on Tuesday.

On Tuesday, the state-backed Global Times ran an editorial saying that abandoning the testing site “would bring huge benefits to the region.”

Many doubt North Korean leader Kim Jong Un will ever fully relinquish his expensive and treasured nuclear weapons, but even if he curtails his program, analysts warn it will be a long process.

“I am concerned that Kim Jong Un may take unilateral actions that are hard to dispute – like closing the test site – and implement them without any observation,” said Sharon Squassoni, a research professor at the Institute for International Science and Technology Policy in Washington. “This would set up a complicated situation wherein North Korea was taking actions that we would normally applaud, but without any verification.”

(Additional reporting by Christine Kim in SEOUL, Matt Spetalnick in WASHINGTON, and Christian Shepherd in BEIJING; Editing by Soyoung Kim and Gerry Doyle)

Closing North Korea nuclear test site an important step, U.N. chief says

U.N. Secretary-General Antonio Guterres arrives for a news conference in Vienna, Austria, May 14, 2018. REUTERS/Leonhard Foeger

VIENNA (Reuters) – Irreversibly closing North Korea’s nuclear test site is an important step that could pave the way for progress at talks between U.S. President Donald Trump and North Korean leader Kim Jong Un, U.N. Secretary-General Antonio Guterres said on Monday.

North Korea gave details on Saturday on the planned dismantling of the Punggye-ri site where it is believed to have carried out all six of its nuclear tests.

The official Korean Central New Agency said it would take place between May 23 and 25 and involve collapsing all the site’s tunnels with explosions, blocking its entrances, and removing all observation facilities, research buildings and security posts.

“I would like to welcome that and to say that the irreversible closure of the site will be an important confidence-building measure that will contribute to further efforts towards sustainable peace and verifiable denuclearization of the Korean peninsula,” Guterres said in a statement after meeting Austria’s chancellor in Vienna.

“And I look forward to this positive momentum being consolidated at the summit between the leaders of the United States and North Korea,” he said in the remarks to reporters after his meeting with Chancellor Sebastian Kurz.

Trump and Kim are due to hold talks in Singapore on June 12, the first-ever meeting between a sitting U.S. president and a North Korean leader.

After North Korea’s announcement on Saturday, Trump said on Twitter: “Thank you, a very smart and gracious gesture!”

(Reporting by Francois Murphy; Editing by Toby Chopra)

North Korea may have resumed tunneling at nuclear test site

North Korean leader Kim Jong Un salutes as he arrives to inspect a military drill at an unknown location, in this undated photo released by North Korea's Korean Central News Agency (KCNA)

WASHINGTON (Reuters) – Satellite images show that North Korea may have resumed tunnel excavation at its main nuclear test site, similar to activity seen before the country’s most recent nuclear test in January, a U.S. North Korea monitoring website reported on Wednesday.

The 38 North website, run by the Johns Hopkins University’s School of Advanced International Studies, said such activity could be carried out as part of preparations for a nuclear test, as was the case in January, or to conceal such preparations.

It said commercial satellite images of the West Portal of the Punggye-ri test site taken on Tuesday showed two small ore carts on a track crossing a road from a tunnel entrance.

“The presence of the two carts … and the absence of any notable changes in the spoil pile suggests that tunnel excavation operations are about to resume, or have recently resumed, for the first time this year,” the 38 North report said.

The report said the images also showed limited movement of vehicles and equipment at the site’s North Portal, where the past three North Korean nuclear tests took place, compared to images taken on April 14.

“These activities by themselves do not establish that test preparations are imminent. However, the possibility of an impending test cannot be ruled out,” the report said.

“Pyongyang has clearly demonstrated, with its fourth nuclear detonation this past January, the ability to conduct detonations on short notice while masking indicators of its preparations from satellite view.”

A South Korean official declined to comment on any new intelligence reports of activities at the site but said the military was on high alert over the possibility that the North could conduct a nuclear test at any time.

North Korean leader Kim Jong Un said in March that his country has miniaturized a nuclear warhead and ordered tests of a nuclear warhead and ballistic missiles in defiance of U.N. sanctions.

38 North reported in early December that satellite photographs from the two previous months indicated North Korea was digging a new tunnel for nuclear testing.

North Korea conducted its fourth nuclear test on Jan. 6 and has vowed to conduct more, despite the stepped up international sanctions.

Some experts expect North Korea to conduct a fifth nuclear test before a ruling party congress in early May, following an embarrassing failure in the test of an intermediate-range missile last week.

The top U.S. diplomat for the Asia-Pacific region warned on Tuesday that a fifth North Korean nuclear test could trigger new sanctions including an effort to choke off hard currency earnings by its workers abroad.

(Reporting by David Brunnstrom; additional reporting by Jack Kim in Seoul; Editing by Tom Brown and Raju Gopalakrishnan)