A trilateral meeting on gas between the EU, Russia and Ukraine will take place between June 27 and 29, but the exact date has not yet been decided, Russian Energy Minister Alexander Novak told reporters.

"Between June 27 and 29 [inclusive]," he said adding that a decision had not yet been reached. He also said the term of validity of Ukraine's gas discount had not been determined yet either.

Russia is considering offering Naftogaz Ukrainy a discount on the price of gas - in the form of a reduced export duty - not only for the third quarter but until the end of the year, Novak said at the beginning of June.

A final discussion on the issue of the gas volume that Ukraine must pump into underground storage to increase inventories to 19 billion cubic meters of active gas will be held during a trilateral meeting planned for the end of June, he said at the time.