The Russian gas company Gazprom has questioned the continued operation of the Nord Stream 1 pipeline against the background of the repair of a necessary turbine in Canada.
Gazprom has not yet received written confirmation that the repaired turbine from Canada will actually be delivered to Siemens, the company responsible for the installation, the Russian group said in a statement on Wednesday.
"Under these circumstances" Gazprom cannot guarantee the future operation of the line.
Referring to the defective turbine, Russia had already throttled gas supplies through the Baltic Sea pipeline in mid-June.
The turbine was then taken to a Siemens plant in Canada for repairs.
Due to Canadian sanctions against Russia, it was initially not clear whether the device, which had since been repaired, could be returned.
However, the government in Ottawa gave the green light for the export over the weekend.
The Siemens group announced that it would install the turbine as soon as possible.
"Gazprom does not have a single document allowing Siemens to take the gas turbine engine that is currently being repaired in Canada out of the country," the Russian company said.
Regular maintenance work on the Nord Stream pipeline also began on Monday, meaning that no gas is flowing through it for the time being.
The work should take around ten days.
However, there were doubts as to whether gas would actually flow again after that.