Russian Energy Minister Alexander Novak said Tuesday Moscow would cut gas supplies to Ukraine by Wednesday at the latest. He told Vesti FM Radio the move was required as Kyiv had not paid upfront for more deliveries.

Novak complained that Ukrainian authorities were not doing enough to allow repair crews to restore power to Crimea, citing "some kind of political motivation" not to ease the plight of 938,000 residents there remaining without electricity, waiting for Russia to sent 300 mobile generators to the peninsula as an interim solution.

In retaliation for Kyiv's unwillingness to step into action, Novak threatened to also halt coal deliveries to Ukraine.

Provocations on both sides

"Russia delivers coal to the Ukrainian energy sector," the minister said. "We could - and maybe in this situation we need to - take a decision about halting supplies of coal by our commercial organizations, which deliver coal to Ukrainian power stations."

The threat pronounced by Russia's energy minister ushered in another round of tension between the two nations and was partly provoked by Kyiv a day earlier when the government came out in support of halting the movement of goods to Crimea.

The move came unexpectedly amid a relative lull in fighting in separatist eastern Ukraine.

hg/tko (Reuters, AFP)