The Kremlin said on Thursday that all difficulties with the supply of Russian natural gas to Europe were caused by Western restrictions, after a major gas pipeline was restarted at below capacity following maintenance.

Russia resumed pumping natural gas via the Nord Stream 1 pipeline to Europe earlier on Thursday after a 10-day outage, allaying Europe's immediate winter supply fears after President Vladimir Putin had warned that flows could be cut further or stopped.

Thursday's flows were back at 40% capacity, Nord Stream figures showed. Russian energy giant Gazprom cut the flows via the pipeline last month, saying that a pumping turbine had not been returned from Canada where it was sent for maintenance.

Canada, which had initially withheld the turbine because of sanctions against Moscow over Ukraine, decided to return the equipment, serviced by Siemens Energy, back to Russia.

In a call with reporters, Kremlin spokesman Dmitry Peskov said that Russia remains "a very important and indispensable part of European energy security."

Amid concerns in Europe that Russia might further restrict gas supplies to the continent, Peskov referred to previous Putin comments that Gazprom had always fulfilled its obligations to clients and would continue to do so.

He rebuffed accusations by some Western politicians, including European Commission President Ursula von der Leyen, that Russia was using energy supplies to "blackmail" Europe.

"Putin has quite comprehensively explained, that it's wrong to talk about any pressure, any blackmail. This is an absolutely wrong statement and we categorically deny it," Peskov said.

He said that because of sanctions imposed by the European Union, Nord Stream 1 faced challenges in equipment maintenance.

"Exactly those very restrictions led to the fact that the machines cannot receive the necessary servicing. The restrictions imposed by the Europeans are the reason for their problems."