A power outage in western Ukraine has halted supplies of Russian oil to Europe via the southern spur of the Druzhba pipeline, officials from both countries said on Wednesday, according to Reuters.

Russian oil pipeline monopoly Transneft (TRNF_p.MM) said the outage could affect crude supplies to Slovakia, Hungary and the Czech Republic but that it hoped flows would resume within a day.

"Our Ukrainian colleagues promised us they would resolve the failure within 24 hours," Transneft spokesman Igor Dyomin said.

The Lviv branch of Ukraine`s Emergencies Ministry said on its website that the supplies had been suspended because of localised power cuts due to bad weather.

Dyomin said Transneft was able to keep receiving oil for the Druzhba pipeline from Russian companies for 24 hours.

"We can fill our reservoirs for about one day. We don`t have any losses at the moment, as we are still in a position to receive oil," he said.

In early 2007, Russia briefly closed Druzhba -- which means friendship in Russian -- pipeline after a row with Belarus.

The pipeline pumps more than 1.2 million barrels of crude a day into Europe. Flows of up to about 600,000 barrels per day to Hungary, Slovakia and Czech Republic could be cut due to the accident in Ukraine.