Any European troop contingents deployed to Ukraine would become legitimate targets for Russia’s armed forces, Foreign Minister Sergei Lavrov said in remarks published by state news agency TASS on Sunday.
Lavrov, without providing evidence, also accused European politicians of being driven by “ambitions” in their relations with Kyiv and disregarding the people of Ukraine and of their own nations.
EU chiefs Ursula von der Leyen and Antonio Costa on Saturday vowed the European Union's support for Ukraine would not falter ahead of Ukrainian President Volodymyr Zelensky's talks with US President Donald Trump.
They took part in a call with Zelensky and several leaders before the Ukrainian president's meeting with Trump in Florida on Sunday.
Zelensky on Saturday also met Canadian Prime Minister Mark Carney in Halifax.
"We welcome all efforts leading to our shared objective -- a just and lasting peace that preserves Ukraine's sovereignty and territorial integrity," European Commission President von der Leyen said on X.
"And that strengthens the country's security and defense capabilities, as an integral part of the security of our continent," she added.
"In 2026, the EU Commission will continue to keep up the pressure on the Kremlin, sustain our support to Ukraine, and work intensely to accompany Ukraine on its path toward EU membership," she also said.
Costa, the president of the European Council, which represents the bloc's 27 member states, echoed her promise to continue backing Ukraine, saying on X: "The EU's support for Ukraine will not falter. In war, in peace, in reconstruction."
Costa warned the EU was ready to slap further sanctions on Russia if needed.
He listed EU moves which "have made Ukraine stronger" including "prolonging sanctions against Russia, with further measures under way if need be.”
Costa added: "A strong and prosperous Ukraine in the EU is a core security guarantee. We continue to work for a robust and lasting peace for Ukraine, in close cooperation with our US partners."
Trump and Zelensky will meet at Mar-a-Lago, Trump’s private club in Palm Beach, Florida, where the US president is spending the holidays and has an agenda mostly filled with daily rounds of golf.
Zelensky said the two planned to discuss security and economic agreements and he will raise “territorial issues” as Moscow and Kyiv remain fiercely at odds over the fate of the Donbas region in eastern Ukraine.