Britain has banned the export of submarines to Russia over what it says are advances that pose a national security risk, including the alleged ability to cut undersea cables which carry most global internet communications.

Britain and the U.S. have warned that the Russian Navy could disrupt over $10 trillion in daily transactions by attacking the cables crossing the world’s seas and oceans. Western military experts have suggested that a secret nuclear-powered submarine hit by a fatal fire in July had the ability to probe and possibly even sever undersea communications cables. <

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The British government’s trade agency has announced “national control” measures prohibiting the export of submarines and related equipment, software and technology to Russia.

“This additional control is a consequence of Russia developing certain capabilities — including the ability to track, access and disrupt undersea communication cables,” said the International Trade Department’s export-control unit.

“These activities represent a risk to our national security and the new control is intended to mitigate this risk,” the agency said in a statement Wednesday.

Russia’s Defense Ministry has not yet commented on the latest ban. In 2015, A Defense Ministry-owned news channel had said that Russia can “both cut the special communication cables on the ocean floor and scan the signals they carry” in the event of active hostilities.