Russia's defence ministry on Saturday said that British navy personnel blew up the Nord Stream gas pipelines last month, directly accusing a leading NATO member of sabotaging critical Russian infrastructure.
The defence ministry did not give evidence for its claim.
"According to available information, representatives of this unit of the British Navy took part in the planning, provision and implementation of a terrorist attack in the Baltic Sea on September 26 this year - blowing up the Nord Stream 1 and Nord Stream 2 gas pipelines," the ministry said.
Britain's defence ministry declined immediate comment.
Russia has previously blamed the West for the explosions last month that ruptured the Russian-built Nord Stream 1 and Nord Stream 2 pipelines on the bed of the Baltic Sea.
But Russia has never before given specific details of who was responsible for the damage to the pipelines, previously the largest routes for Russian gas supplies to Europe.
The Kremlin has repeatedly said allegations of Russian responsibility for the damage were "stupid" and Russian officials have said Washington had a motive as it wants to sell more liquefied natural gas (LNG) to Europe.
The United States has denied involvement.
