BONN - Germany is in the dark about how much gas Russia will pump through the Nord Stream 1 pipeline after the end of a 10-day maintenance shutdown that started on Monday, Germany's energy regulator told Reuters.

Governments, markets and companies worry that the shutdown might be extended because of the war in Ukraine, which has triggered an economic standoff between the West and Russia and fears of gas shortages and soaring energy bills.

The Nord Stream 1 pipeline transports 55 billion cubic metres (bcm) a year of gas from Russia to Germany under the Baltic Sea. Maintenance lasts for July 11 to 21.

"As expected, Nord Stream 1 is at zero since this morning," said Klaus Mueller, head of the Bundesnetzagentur.

"What happens at the end of the maintenance, nobody is able to say at this moment. We won't know any time sooner than a day before its scheduled end."

Mueller said that gas consumers have lobbied his agency for priority treatment in the event of potential gas rationing later in the year.

The regulator would base allocation decisions on their social and economic impact and consequences for delivery chains, Mueller said. Such decisions would be taken in October with the help of an IT platform, he added.

"The Bundesnetzagentur has been confronted with a lot of letters and requests since the beginning of March, in which industry leaders but also entire regions and companies tell us that gas is indispensable for them," he said.

"I understand this but the scenario is such that we would have too little gas and what we need is proposals where we can save gas."

Ukraine and its allies accuse Moscow of using spurious pretexts to strangle gas flows in retaliation for sanctions over the invasion of Ukraine, which Russia describes as a "special military operation".

The Kremlin denies any such manipulation of gas flows or using energy as a political weapon.

Dwindling gas flows and rocketing prices have sparked recession fears in Germany and prompted utility group Uniper to ask the government for a bailout.

(Reporting by Vera Eckert and Andreas Kranz Writing by Matthias Williams Editing by David Goodman)