LONDON—Britain’s military exposed a month-long, secret Russian submarine operation carrying out “nefarious activity” against the U.K.’s critical undersea infrastructure like pipelines and telecommunications cables, the latest incident in a global proxy battle targeting key underwater assets.
Defense Secretary John Healey Thursday said the British Navy, together with partners like Norway, tracked three Russian submarines for a month in the North Atlantic, one of which was being used as a decoy while two others lurked over critical undersea pipelines and cables.
He accused Russia of trying to take advantage of the turmoil in the Middle East to catch the U.K. unaware. Healey said he was confident no damage was done, but warned Russian President Vladimir Putin that future damage would be met with “serious consequences.”
“We see you, we see your activity over our cables and our pipelines,” Healey said at a news conference.
Russia’s Embassy in London didn’t immediately respond to requests for comment.
NATO and western allies have said Russia and China appear to be behind a covert effort to map and pinpoint vulnerabilities to pipelines that provide crucial energy and communications near rival countries like Taiwan and in Northern Europe.
Undersea cables were cut twice in the Baltics in 2024 by tankers dragging their anchors, one linked to Russia and the other to China, prompting NATO to launch a policing operation called Baltic Sentry early last year. This year, NATO has also launched Arctic Sentry to patrol the Arctic Ocean. Taiwan has also suffered several such cuts.
Russia and China have denied any wrongdoing. And Russia was hit by the bombing of its underwater Nord Stream 2 gas pipeline in 2023 by agents linked to Ukraine.
Just over a month ago, the U.K. and allies detected unusual Russian activity in the North Atlantic. They discovered a Russian Akula-class nuclear-powered attack submarine, which Healey said was being used as a decoy to divert attention from two specialist submarines from the Kremlin’s Main Directorate for Deep-Sea Research, an elite unit of the Russian military specialized in deep-sea work. Those submarines were discovered over critical assets like undersea pipelines.
“Our armed forces left them in no doubt that they were being monitored, that their movements were not covert, as President Putin planned, and that their attempted secret operation had been exposed,” Healey said.
Last year, a Russian spy ship called the Yantar was discovered in British waters and chased away, only months after it was seen near undersea cables. The ship, also linked to the Kremlin’s deep-sea unit, has crisscrossed the globe for a decade mapping vital arteries for the global economy that run along the sea floor, western officials say.
Since Russia’s invasion of Ukraine in 2022, Russia has engaged in a hybrid war with Ukraine’s European allies, from cyberattacks to drone incursions over airports and key military installations.
Write to David Luhnow at david.luhnow@wsj.com
