A spokesperson for the Russian Energy Ministry said Monday it was postponing trilateral talks with the European Union and Ukraine.

Talks were scheduled for Saturday. A ministry spokesperson told state news agency RIA Novosti an alternate date depended on Energy Minister Alexander Novak's schedule.

"We told the European Commission that the proposed date is not suitable for us," the spokesperson said. "Another date is being discussed."

The European Union last week enforced new sanctions on the Russian energy sector in response to ongoing crises in eastern Ukraine.

A government decision in Kiev in November to suspend efforts to join the EU sparked political upheaval in Ukraine, a former Soviet republic. That, in turn, led to intervention by Russia, which annexed the Crimean Peninsula and has supported separatists in eastern Ukraine.

On Saturday, Ukrainian Prime Minister Arseniy Yatsenyuk submitted to Parliament the text of an association agreement with the EU.

Europe is trying to avert a repeat of an energy crisis that erupted in 2006 and 2009 when Russian natural gas company Gazprom cut gas supplies to Ukraine because of contractual disputes.

Europe gets about a quarter of its gas needs met by Russia, though most of that runs through the Soviet-era pipeline network in Ukraine.