France on Tuesday accused Moscow of using energy supplies as "a weapon of war" as Russian gas giant Gazprom  reduced deliveries to one of its main utilities and prepared to halt flows along the major pipeline to Germany from Wednesday.

European governments are trying to find a response to soaring energy costs for businesses and households and to find alternatives to Russian supply to store for winter.

Western nations fear that Moscow is driving up gas prices to try to weaken their resolve in opposing its invasion of Ukraine, a tactic Ukraine's President Volodymyr Zelenskiy on Monday dubbed economic terrorism. Moscow denies it is doing this.

The Nord Stream 1 pipeline, the main conduit for Russian gas into Europe, has become a flash point in the economic war between Moscow and Brussels. Europe is already on notice that supplies will be squeezed as Gazprom shuts off Nord Stream 1 from Wednesday to Friday for maintenance.

Kremlin spokesman Dmitry Peskov said on Tuesday that technological problems caused by Western sanctions are the only thing standing in the way of supplying gas via Nord Stream 1.

But France's Energy Transition Minister Agnes Pannier-Runacher said on Tuesday: "Very clearly Russia is using gas as a weapon of war and we must prepare for the worst case scenario of a complete interruption of supplies."

She was speaking to France Inter radio after French utility Engie said it would receive less gas from Gazprom from Tuesday because of an unspecified contractual dispute.