Trilateral talks between the European Union, Ukraine and the Kremlin on the transit of gas through the territory of Ukraine are scheduled for early July.

"Time is a precious commodity. I hope to start working with Russia & Ukraine on the trilateral gas agenda in early July. Complex negotiations ahead," European Commission Vice President Maros Sefcovic wrote on Twitter.

Read alsoSwedish court suspends Stockholm Arbitration award in UA-RU gas transit dispute

In March, the EU leadership announced its intention to hold talks after the Russian gas monopoly Gazprom had unilaterally broken all gas contracts with Naftogaz in response to Ukraine's victory in the Stockholm Arbitration Court over the two deals: the transit of Russian gas to the EU and gas purchase from the Russian Federation.