The Slovak Foreign Ministry summoned Ukrainian Ambassador to Bratislava Myroslav Kastran on Jan. 29 after Kyiv criticized the country's Prime Minister Robert Fico for wanting to continue Russian gas supplies to Slovakia, it said on social media.
The move came as relations between Fico and President Volodymyr Zelensky have become increasingly tense over this month.
In his recent remarks on Jan. 28, the Slovak prime minister called Zelensky "the enemy" of Slovakia.
"Many in Europe... have chosen to preserve their independence and sovereignty. But not Mr. Fico. He chooses Moscow over America and other partners who can supply his country with gas on commercial terms. This is his mistake," Ukraine's president said in response.
According to the ministry's statement, the Slovak ministry delivered the Ukrainian ambassador "a strong protest" against statements by the Ukrainian side, without specifying which ones.
"(These statements) are considered interference in the internal affairs of the Slovak Republic," the ministry said.
Ukraine's Foreign Ministry is yet to comment on this move.
Fico, a pro-Russian politician who has long opposed military aid to Ukraine, has escalated threats against Kyiv following the termination of Russian gas transit via Ukrainian territory on Jan. 1.
He has threatened to limit aid to Ukrainians and cut off electricity supplies amid an energy crisis brought on by Russia's relentless attacks against Ukraine's power grid.
As tensions mount, Zelensky and Fico signaled in mid-January they may hold talks.
Fico's friendliness towards the Kremlin has sparked outrage both at home and abroad. His meeting with Russian President Vladimir Putin in Moscow in December drew condemnation from other European leaders.
Mass protests erupted in Bratislava in early January, with thousands chanting "We are not Russia."
Olena Goncharova
(Updated: )
