Russian oil has stopped flowing to Hungary through the “Druzhba” (Friendship) pipeline transiting Ukraine, the Hungarian oil company MOL confirmed on Tuesday evening. 

The official reason given by the Ukrainian side was that a Russian air strike hit a transformer station near the border with Belarus, which supplies electricity to one of the pumping stations, needed for operations.

Ukraine has also informed Russia’s Transneft that service was suspended due to a “drop in voltage,” according to Igor Demin, a spokesman for the Russian oil giant.

Crude oil deliveries to Hungary, Czechia and Slovakia have been “temporarily halted,” MOL said in a statement.

“We are monitoring the events and, together with the Ukrainian partners, we are examining the conditions for restarting the Friendship pipeline,” the Hungarian oil company added.

According to MOL, there were adequate reserves of oil to ensure the operations of the Szahahalombatta refinery until the pipeline is back in service.

Hungarian PM Viktor Orban has called an emergency meeting of the national security council, to address both the pipeline shutdown and claims that a stray Russian missile had struck a village in Poland, according to his spokesman Bertalan Havasi.

Although the EU banned the imports of Russian oil by sea in June, Brussels carved out an exemption for Hungary, Czechia and Slovakia to continue buying oil from Moscow via the pipeline.

Built in the 1960s, Druzhba runs over 4,000 kilometers from Tatarstan in Russia to Hungary and what used to be East Germany and Czechoslovakia. Some 1,490 km of the pipeline pass through the territory of Ukraine. The pipeline splits in Uzhgorod to Druzhba-1, which goes to present-day Slovakia, and Druzhba-2, which goes to Hungary.