Russia's Gazprom will further reduce natural gas flows through a major pipeline to Europe to 20 per cent of capacity, citing repairs of equipment.
The Russian state-owned company tweeted on Monday that it would reduce "the daily throughput" of the Nord Stream 1 pipeline to Germany to 33 million cubic metres as of Wednesday.
The head of Germany's network regulator confirmed the reduction.
"The halving of the nomination of Nord Stream1 was announced for the day after tomorrow," tweeted Klaus Mueller.
It comes after Gazprom raised questions earlier on Monday about the return of a part that has been at the centre of tensions over natural gas deliveries through the pipeline, saying that it isn't satisfied with documents it has received.
The company reduced the gas flow through the Nord Stream 1 pipeline by 60 per cent in mid-June, citing alleged technical problems involving the equipment that partner Siemens Energy sent to Canada for overhaul and couldn't be returned because of sanctions over Russia's invasion of Ukraine.
Canada subsequently allowed the turbine for a compressor station at the pipeline's Russian end to be delivered to Germany. That is where the German government said it was last week.
Its return to Russia has turned into a protracted saga, underlining tensions over the war and raising the possibility of even less gas flowing through the pipeline under the Baltic Sea to Germany.
Gas is used to keep industry humming, generate electricity and heat homes in the winter, and concerns are rising about a possible recession if Europe does not save enough gas and rationing is required to get through the cold months.
Germany has rejected Gazprom's technical explanation for the gas reduction, saying repeatedly that it was only a pretext for the Kremlin's political decision to sow uncertainty and further push up energy prices. It has said the turbine was a replacement that was only supposed to be installed in September.
Deliveries stayed at 40 per cent of full capacity when Nord Stream 1 reopened after 10 days of scheduled maintenance last week.
In a statement Monday on Twitter, Gazprom said it had received documents for the turbine issued by Canadian authorities but after studying them, "had to conclude that they do not eliminate the previously identified risks and give rise to additional questions."
It also asserted that issues regarding European Union and British sanctions "remain unresolved for Gazprom," though that resolution is important for delivering the turbine "and performing urgent major repair of other turbine engines" for the same compressor station.
The company said it had requested "prompt support" from Siemens Energy to clarify. Germany says all concerned have been informed that the part isn't subject to EU sanctions, and Siemens Energy said it had no update.
The German government said last week that the reduction in gas flows confirmed that the country can't rely on Russian deliveries, announcing that it would step up its gas storage requirements and take further measures to save gas. Russia recently has accounted for about a third of the country's gas supplies.