Polish pipeline operator PERN said on Wednesday that its automated detection systems had found a leak in one line of the Druzhba oil pipeline, which carries oil from Russia to Europe.

PERN said that it was still unclear what might have caused the leak, which was detected on Tuesday evening.

According to Polish Prime Minister Mateusz Morawiecki, it is too early to say whether the leak was accidental damage or was caused by sabotage.

"Many steps point straight to the Kremlin, but we want to be very responsible and only then confirm our assumptions," he told Polish state-owned radio broadcaster PR3.

In a statement on its website, PERN said the leak was located some 70 kilometers (44 miles) from the western city of Plock and was on the main route transporting crude oil to Germany.

"The cause of the incident is not known for the moment. Pumping in the affected line was immediately stopped. Line 2 of the pipeline is functioning normally," PERN said.

A spokeswoman for the Czech pipeline operator MERO said no change in flows to the Czech Republic had been detected.

Concerns about energy security

The reports come after blasts caused severe damage to pipelines carrying Russian gas in the Baltic Sea, raising fears that critical energy infrastructure could be in danger of sabotage amid tensions over Moscow's invasion of Ukraine.

Europe could face a severe energy crisis this winter after Russia cut gas deliveries in what many see as a "weaponization" of energy supplies.

German supply is 'secure'

Last year, Russia supplied some 35% of Germany's crude oil supply. That share has been cut in response to the invasion, and Germany is now attempting to phase out the remaining amount ahead of an impending European Union embargo on most Russian imports.

The German Economy Ministry said on Wednesday that Germany's Schwedt and Leuna refineries were still receiving oil via the pipeline and that the supply was "secure."

However, the Schwedt refinery, which supplies 90% of Berlin's fuel, said in an emailed statement to Reuters that deliveries were ongoing but reduced.

The Druzhba oil pipeline transports Russian oil to much of central Europe, including Germany, Poland, Belarus, Hungary, Slovakia, the Czech Republic and Austria.

Its name means "friendship" in Russian.

tj/wmr (Reuters, AFP)