By Phil Stewart and Idrees Ali

WASHINGTON (Reuters) – Acting U.S. Defense Secretary Patrick Shanahan told civilian leaders of the U.S. military on Wednesday to remember “China, China, China” even as America fights militants in places like Syria and Afghanistan, a U.S. defense official said.

The comments underscoring Shanahan’s focus on China came during his first meeting with secretaries of the U.S. military branches since taking over for Jim Mattis, who resigned as defense secretary over policy differences with President Donald Trump.

The U.S. official, who spoke on condition of anonymity, did not elaborate on Shanahan’s views on China. But other officials have described him as a driving force behind the Pentagon’s toughening stance toward Beijing, which includes branding China as a strategic competitor in the 2018 National Defense Strategy.

Shanahan, a former Boeing executive, had been Mattis’ deputy and it was unclear how long he will remain in the role of acting secretary. Trump could face an uphill battle finding someone who can be confirmed by the Senate in the wake of Mattis’ acrimonious departure.

Several candidates long rumored to be interested in the post had indicated in recent days, some publicly, that they did not want to succeed Mattis, who was respected in the Pentagon and enjoyed bipartisan support when he departed on Dec. 31.

Trump acknowledged that Shanahan could be in the job for a long time and the Pentagon appeared to be taking steps to prepare for an extended tenure — including naming someone to fulfill the role of deputy defense secretary provisionally.

David Norquist, the Pentagon’s comptroller, will perform the duties of the deputy as well as retain his current title.

Shanahan, in a statement on Tuesday shortly after taking over the job, said he looked “forward to working with President Trump to carry out his vision” which includes a surprise withdrawal from Syria and an expected drawdown in Afghanistan, America’s longest war.

Shanahan, best known for his focus on internal Pentagon reform and his private-sector experience, had spent three decades at Boeing and was the general manager for the 787 Dreamliner passenger jet before he joined the Pentagon last year.

“Acting Secretary Shanahan told the team to focus on the national defense strategy and to keep this effort moving forward,” the U.S. defense official told reporters.

“While we’re focused on ongoing operations, acting Secretary Shanahan told the team to remember China, China, China.”

Shanahan was due to participate in a cabinet meeting later on Wednesday.

(Reporting by Phil Stewart and Idrees Ali; Editing by Chizu Nomiyama and David Gregorio)