Ukraine agreed to start paying a gas debt it owed Russia this week, in a bid to resolve a gas supply dispute between the two countries, said European Union Energy Commissioner Guenther Oettinger in Berlin on Monday.

Ukraine agreed to pay 2 billion U.S. dollars back to Russia by Thursday for the gas delivered since July last year, said Oettinger in a press conference started nearly two hours later than scheduled, following a meeting with Ukraine Energy Minister Yuri Prodan and his Russian counterpart Alexander Novak.

The deal was subject to the approval of governments of both sides, Oettinger said, adding that further talks would be held on Friday in Berlin.

The three officials have met twice for solutions to dispute over gas imports from Russia to Ukraine.

According to Russia, Ukraine has not paid for the gas it imported in full for months, accumulating a debt of over 3.5 billion U.S. dollars. Russia has threatened that if Ukraine failed to pay the bill by the end of May, it would supply gas on a pre-payment basis from June.