Ukrainian President Volodymyr Zelenskiy accused Slovakia's Prime Minister Robert Fico on Saturday of opening a "second energy front" against Ukraine on the orders of Russia, as a gas transit dispute between the countries deepened.

Slovakia will consider reciprocal measures against Ukraine such as halting back-up electricity supplies after Jan. 1 if Kyiv, as expected, stops the transit of Russian gas to Slovakia, Prime Minister Robert Fico said on Friday.

The agreement allowing Russian gas to transit through Ukraine to Europe will expire in a few days. Our eastern neighbors have already announced that they do not intend to extend it. The Kremlin is trying to put on a brave face,

The future of gas transit through Ukraine is at a turning point. If a last-minute deal isn’t struck by Wednesday, billions of cubic meters in gas flows could come to a halt.

President Vladimir Putin said on Thursday there was no time left this year to sign a new Ukrainian gas transit deal, and laid the blame firmly on Ukraine for refusing to extend the agreement that brings gas to Slovakia,

Slovak Prime Minister Robert Fico announced on Dec. 27 that his government will evaluate potential reciprocal measures against Ukraine, including halting electricity supplies, if Ukraine stops the transit of Russian gas to Slovakia after January 1.

Prime Minister Robert Fico’s warning comes as the gas transit deal between Russia and Ukraine is set to expire at the end of the year.

Benchmark European natural gas futures jumped as much as 5% in early trading Friday after Russia's President Putin said it would be impossible to reach agreement on any new transit contract for the flow of natural gas through Ukraine to Europe before year’s end.