Druzhba flows to Slovakia and Hungary restarted on Wednesday after Hungarian oil group MOL paid transit fees through Ukraine instead of Russia, and Pantucek said its customer PKN Orlen was taking the same steps on Thursday.

"As oil flows today to Slovakia and Hungary, MOL as the customer took practical steps for the pipeline to operate...I am informed by our customer that it is taking identical steps today so I expect that very soon, tomorrow or the day after tomorrow oil will be flowing here as well," Pantucek said.

PKN had no immediate comment and PKN Orlen's Czech unit ORLEN Unipetrol declined to comment.

MOL and its Slovak subsidiary Slovnaft paid the Ukrainian oil transit company fees for August oil transit through Druzhba on Wednesday, replacing a payment from Russia' pipeline monopoly Transneft which the Russian firm said was made impossible by Western sanctions.

Slovnaft said the fees would be settled with the Russian side through mutual crediting.

(Reporting by Jan Lopatka; additional reporting by Anna Koper in Warsaw; editing by Jan Harvey and Jason Neely)