Ukrainian President Volodymyr Zelensky blamed Slovak Prime Minister Robert Fico for the opening “second energy front” against Ukraine at the behest of Russia, as the gas dispute between the two countries escalates.

Ukraine exports Russian natural gas that passes through its territory to several European countries, including Slovakia, but is expected to cut off the flow when the transit agreement it signed with Russia expires on December 31.

Fico, who visited Vladimir Putin in Moscow this week, said on Friday that Slovakia would consider in response measures such as the cessation of exports of electricity to Ukraine if Kiev cuts off gas transit on January 1.

“It appears that Putin ordered Fico to open a second energy front against Ukraine at the expense of the interests of the Slovak people,” wrote Volodymyr Zelensky mockingly in X in his new fire against the Slovak prime minister.

Slovakia is seeking to keep Russian gas flowing through Ukraine, saying alternative routes drive up costs and hurt its own transit businesses, causing it to lose 500 million euros in fees.

Ukraine has said it will not sign a new gas transit deal with Moscow because of a 2022 Russian invasion.

Ukraine has been forced to import electricity from many of its neighboring countries since Russia systematically attacked its energy infrastructure destroying the country’s energy potential.

The Ukrainian president said that from Slovakia to Kyiv imports 19% of the energy and that it is working with the European Union to increase supplies.

“Slovakia is part of the single European energy market and Fico must respect common European rules,” wrote Volodymyr Zelensky clarifying that cutting energy exports to Ukraine will mean a loss of $200 million a year for Slovakia.

“Today, I looked at the details of electricity imports from the EU to Ukraine via Slovakia — which represent about 19% of the total volume. Fitzo won’t cut off our imports. We work with other neighbors in the EU” Zelensky added in a new message.

“I have instructed our officials to work with the European Commission and all our European partners to do everything possible to maintain the stability of the single European energy system and uphold European energy rules.”

“Whatever Putin said to Fitzgerald during his visit to the Kremlin, European rules must override anyone’s ties to Moscow.” repeated the Ukrainian president.