Russia is throttling back capacity on a major pipeline that sends crude oil to global markets, driving prices higher and raising fears that Moscow was prepared to retaliate against western sanctions by curbing its own energy supplies.

Up to 1mn barrels a day of oil shipped through the Caspian Pipeline Consortium’s pipeline from central Asia to the Black Sea could be cut for up to two months while repairs are made to storm-damaged loading facilities, Russia’s deputy energy minister said in a statement on Tuesday carried by the news agency Tass.

The supply interruption comes on the eve of US president Joe Biden’s trip to Europe, where EU countries are expected to discuss imposing sanctions on Russia’s oil sector in response to country’s invasion of Ukraine. The US has already banned Russian petroleum imports.