Gazprom said Friday that a gas pipeline to Germany due to reopen at the weekend would remain shut until a turbine is repaired, cutting off indefinitely a key supply route to Europe.
In a statement, state-owned gas giant Gazprom indicated it had discovered "oil leaks" in a turbine during a planned three-day maintenance operation.
Gazprom added that "until it is repaired... the transport of gas via Nord Stream is completely suspended."
Resumption of deliveries via the pipeline which runs from near St Petersburg to Germany under the Baltic Sea, had been due to resume on Saturday.
Gazprom said it had discovered the problems while carrying out maintenance with representatives of Siemens, which manufactured the turbine in a compressor station that pushes gas through the pipeline.
On its Telegram page it published a picture of cables covered in a brown liquid.
Earlier in the day, the Kremlin warned the future operation of the Nord Stream pipeline, one of Gazprom's major supply routes, was at risk due to a lack of spare parts.
"There are no technical reserves, only one turbine is working," Kremlin spokesman Dmitry Peskov told reporters.
"So the reliability of the operation, of the whole system, is at risk," he said, adding that it was "not through the fault" of Russian energy giant Gazprom.
Following the imposition of economic sanctions over the Kremlin's invasion of Ukraine, Russia has reduced or halted supplies to different European nations, causing energy prices to soar.
The Kremlin has blamed the reduction of supplies via Nord Stream on European sanctions which it says have blocked the return of a Siemens turbine that had been undergoing repairs in Canada.
Germany, which is where the turbine is located now, has said Moscow is blocking the return of the critical piece of equipment.