The controversial Nord Stream 2 Baltic Sea pipeline began being filled with gas on Monday, according to the pipeline's builder and operator.
While Nord Stream 2 AG did not provide a date for the pipeline to enter into service, experts suggest that gas deliveries could begin later in October.
Russian energy giant Gazprom has announced it plans to pump 5.6 billion cubic metres of gas through Nord Stream 2 this year alone.
According to the Russian government, the commissioning of the pipeline, which runs from Vyborg in northern Russia through the Baltic Sea to the eastern German town of Greifswald, could help to address the current shortfall in European gas supplies, which has sent gas prices soaring in recent months.
The 1,230-kilometre-long twin pipeline is designed to deliver 55 billion cubic metres of gas to European markets annually, or enough to supply 26 million households.
The project has strained trans-Atlantic unity, with critics warning against European energy dependence on Russia. Ukraine has been particularly irate over the project as it faces the loss of millions of dollars in annual transit fees currently paid to transport gas to Europe through its territory.
The US has also been deeply opposed to the project, even imposing sanctions on it to cause construction delays. Washington fears the pipeline will be used as a geopolitical bargaining tool by Moscow.
A US-German agreement stipulating Russia be sanctioned should Nord Stream 2 one day indeed be used as a bargaining chip, appears to have appeased the US government, and though while still against the project, the Biden administration has given up its attempts to block it.