Russia's top spy said on Friday that Moscow had intelligence indicating that the West was behind what he said was a "terrorist act" against the Nord Stream gas pipelines under the Baltic Sea.
A sharp drop in pressure on both pipelines was registered on Sept 26 and seismologists detected explosions, triggering a wave of speculation about who might have sabotaged one of Russia's most important energy corridors.
The European Union said it suspected sabotage caused the damage to the Gazprom-led Nord Stream 1 and 2 pipelines in Swedish and Danish waters. The White House has dismissed Russian allegations it was behind the incidents.
"We have materials that point to a Western trace in the organisation and implementation of these terrorist acts," Sergei Naryshkin, the director of Russia's Foreign Intelligence Service (SVR), was shown telling reporters on state television, news agency Reuters reported.
The spy chief's remarks are the most direct public accusation against the West from a senior Russian official. He did not say what evidence Russia had, but said the West was trying to obscure who carried out the attack.
"The West is doing everything to hide the true perpetrators and organizers of this international terrorist act," Naryshkin said. The SVR is the direct successor to the once mighty First Chief Directorate of the Soviet-era KGB.
President Vladimir Putin on Thursday said the "unprecedented sabotage" against the Nord Stream gas pipelines was "an act of international terrorism."
The Kremlin declined to comment on Naryshkin's remarks but said there needed to be a thorough international investigation into the incidents.
Sweden's energy minister said on Friday it was "very likely" that the attack on the pipelines was done on purpose by a state actor.
Since the ruptures were first detected earlier this week, officials in Moscow have hinted that the West, led by the US, could be behind the attack. On Thursday, Russian Foreign Ministry spokeswoman Maria Zakharova said Washington stood to gain from the pipelines being disrupted.
Neither Nord Stream 1 or 2 were in operation when the ruptures were discovered on Monday, but both contained gas. Nord Stream AG, the operator for the Nord Stream 1 pipeline, said it expects the gas leak to stop by Monday, but that it has not been able to access the area to assess the damage.