WASHINGTON (Reuters) – The presence of Russian submarines and spy ships near undersea cables carrying most global Internet communications has U.S. officials concerned that Russia could be planning to sever the lines in periods of conflict, the New York Times reported on Sunday.

The Times said there was no evidence of cable cutting but that the concerns reflected increased wariness among U.S. and allied officials over growing Russian military activity around the world.

The newspaper quoted naval commanders and intelligence officials as saying they were monitoring significantly greater Russian activity along the cables’ known routes from the North Sea to Northeast Asia and waters closer to the United States.

“It would be a concern to hear any country was tampering with communication cables; however, due to the classified nature of submarine operations, we do not discuss specifics,”

U.S. Navy spokesman Commander William Marks told the Times.

Last month, the United States closely monitored the Russian spy ship Yantar, which equipped with two self-propelled deep-sea submersible craft, cruised off the U.S. East Coast toward Cuba, where one cable lands near the U.S. naval base at Guantanamo Bay, according to the Times.

Naval officials said the ship and the submersible craft were capable of cutting cables miles (km) deep beneath the sea, the Times said.

While cables are frequently cut by ship anchors or natural disasters and then quickly repaired, Pentagon officials are concerned that the Russians seem to be looking for vulnerabilities at much greater depths where cable breaks are harder to locate and repair, the paper said.

It said the cables carried more than $10 trillion daily in global business and more than 95 percent of daily communications.

(Reporting by Peter Cooney; Editing by Eric Walsh)