U.K. says it stopped Moscow efforts to survey undersea cable network, caused Russian subs to retreat

British officials said Thursday they foiled a plan by Moscow to survey vital undersea cable networks in the North Atlantic by forcing at least three Russian submarines to retreat and return to their bases.

British warships and military aircraft identified a Russian attack submarine entering international waters in the North Atlantic several weeks ago and began tracking it around the clock, Defense Secretary John Healey told reporters.

After determining the Akula-class attack submarine was deployed as a distraction, Britain worked closely with allies, including Norway, to track other Russian subs conducting “nefarious activity” over critical undersea infrastructure in other locations, he said.

The other Russian vessels were from the Main Directorate of Deep Sea Research, known as GUGI. The British Royal Navy deployed one of its frigates, the HMS St. Albans, along with Merlin helicopters and support ships to track the attack submarine as it operated near British territorial waters.

“I want to pay tribute to the U.K. personnel who spent many days tracking these Russian submarines in extremely challenging and treacherous conditions,” Mr. Healey said during a press conference. “While the eyes of many —understandably — were on the Middle East, our British armed forces were simultaneously responding to rising Russian threats north of the U.K.”

The Royal Air Force and the Royal Navy deployed sonobuoys — small, tube-shaped acoustic sensors — to detect and track submarines.

British officials described GUGI as Russia’s long-running military program to develop capabilities to survey underwater infrastructure that could be damaged or destroyed during a future conflict.

“While the Russian attack submarine has now headed back towards Russia, the U.K. has kept both naval vessels and aircraft ready to respond should Russian vessels return,” British officials said. “The U.K. continues to closely monitor the situation and is working closely with allies to track and deter any activity that threatens British interests.”