“A discussion will be held on the fulfillment of the complex of measures that were agreed upon on February 12 in Minsk,” Ushakov told journalists.
Ushakov said the telephone conference between Russian President Vladimir Putin, Ukrainian President Petro Poroshenko, French President Francois Hollande, and German Chancellor Angela Merkel was scheduled for 10:00 p.m. Moscow time (19:00 GMT).
Deliveries of Russian gas to Ukraine were suspended last June over Ukraine's debt that exceeded $5 billion at the time. Russian energy giant Gazprom resumed gas deliveries in December under a "winter package" deal signed last year in Brussels.
The deal, which expires on April 1, 2015, stipulates that Ukraine must pay Russia in advance for all future gas supplies. Talks on a "summer package" were expected to start on Monday in Brussels, according to the head of Ukrainian energy company Naftogaz.
The new deal included a ceasefire that came into force on February 15, a pullout of heavy weaponry, already completed by the east Ukrainian Donbas forces. An "all-for-all" prisoner exchange and constitutional reforms were also among the 13 points of the Minsk Agreements.
