PRAGUE (Reuters) - Slovakia has rejected Ukraine President Volodymyr Zelenskiy's accusation that Prime Minister Robert Fico had opened a "second energy front" against Kyiv on the orders of Russia as a gas transit dispute deepened between the countries.

Foreign Minister Juraj Blanar said on Sunday Slovakia was closely monitoring communications from Ukraine regarding Fico's statements and said Zelenskiy's suggestion of an alliance with Russian President Vladimir Putin was "fabricated".

"We fully understand that they are exposed to a long-term war conflict, but that is why they should not create new enemies and fabricate a formation of a second front because member states of the European Union, including Slovakia, support Ukraine and its people," Blanar said in a Facebook post.

Ukraine pumps Russian natural gas through its territory to several European countries including Slovakia but it is expected to halt the flow when the existing transit deal - signed before Moscow's invasion of Ukraine - expires at the end of the year.

Fico, who visited Putin in Moscow a week ago, said on Friday Slovakia would consider reciprocal measures against Ukraine such as halting electricity supplies if Kyiv stops the gas transit from Jan. 1 - spurring Zelenskiy's accusation that Slovakia was opening up a second energy front.

The Slovak prime minister also posted on Facebook on Sunday, calling on the European Commission to pay close attention to the matter and repeating his claims that the loss of gas transit across Ukraine would hit European consumers and businesses.

"We are coming to a conclusion that must be unacceptable for the European Union and its goals," Fico wrote in an open letter. "Unilateral stoppage of transit through Ukraine towards Slovakia will cost European citizens, businesses and infrastructure tens of billions."

(Reporting by Michael Kahn; Editing by David Holmes)