MINSK: Russian, Polish, Ukrainian and Belarusian officials will meet in Minsk on Friday to discuss the recent poor quality of Russian oil supplies that caused deliveries from Russia to be cut short this week.

Representatives of oil transport companies from the four countries, as well as officials from Russia's energy ministry will meet in the Belarusian capital.

Russia's Transneft, Ukraine's Ukrtransnafta, Poland's PERN and Belarus' Belneftekhim will take part in the talks.

Rumours about the poor quality of oil, with excess chloride, have circulated since Wednesday and pushed up the price of the commodity.

The delivery of Russian oil through the major "Druzhba" ("Friendship") pipeline was interrupted Thursday towards Poland, Germany and Slovakia.

Ukrtransnafta announced it will stop Ukraine's transit of the pipeline and warned of the threat of its "complete shutdown".

"Today, the refineries are working at about 50 percent of the delivery level before they had degrading characteristics," said the deputy head of Belneftekhim Vladimir Sizov.

He estimated losses as a result at about $100 million.

Russia's energy ministry said in a statement that it was a working to resolve the issue.

Analyst Mike Lynch called the case "quite strange" and that it could be linked to "technical problems at a Russian refinery."

"It has caused some nervousness in the markets, but it seems the situation can be resolved rapidly," he said.