Russia said on Tuesday it was considering what "further steps" to take in connection with its allegation that Britain was responsible for an attack on the Nord Stream undersea gas pipelines.
Russia's defence ministry said on Saturday that British navy personnel had blown up the Nord Stream pipelines in September, an assertion that London said was false and designed to distract from Russian military failures in Ukraine.
"There is evidence that Britain is involved in sabotage ... a terrorist act against vital energy infrastructure," Kremlin spokesman Dmitry Peskov told reporters.
"Such actions cannot be put aside. Of course, we will think about further steps. It definitely cannot be left like this," Peskov said.
The Kremlin has not provided evidence to support its claims Britain was behind the ruptures on the Nord Stream pipelines, which have threatened to put the multi-billion dollar gas link permanently out of use.
The Kremlin also said no decision had been taken on whether to repair the Russian-controlled pipelines.
Peskov said the Kremlin was awaiting for an expert assessment of the damage and that no decisions had yet been taken on the future of Nord Stream 1 or Nord Stream 2.
Sweden last week ordered additional investigations to be carried out on the damage. Authorities in both Sweden and Denmark have concluded the gas leaks were caused by explosions, but have not said who might be responsible.
(Reporting by Reuters; Editing by Kevin Liffey and Mark Trevelyan)