KIEV (Reuters) – Ukraine, Russia and the European Union could meet for the next round of talks on a new gas deal on Thursday but the date has not yet been confirmed, Ukraine’s energy minister Oleksiy Orzhel said on Monday.

An existing deal on Russian gas supplies to Ukraine and those transiting to Europe expires after Dec. 31. A new agreement has not yet been signed and talks are complicated by issues such as arbitration proceedings and Russia’s annexation of Crimea.

Russian President Vladimir Putin and his Ukrainian counterpart Volodymyr Zelenskiy may also discuss problems in negotiating the deal when they meet other European leaders in Paris on Dec. 9.