Hungary's Prime Minister Viktor Orban met Russian President Vladimir Putin for talks on the fighting in Ukraine, on a trip the EU said threatened to undermine the bloc's stance on the conflict.
President Putin hosted Mr Orban - the friendliest leader in the EU to Moscow - at the Kremlin and at the start of their televised talks said he expected the Hungarian to speak for Europe as the holder of the EU's rotating presidency.
"I understand that this time you have come not just as our long-standing partner but as president of the council," President Putin told Mr Orban, adding that he expected him to outline "the position of European partners" on Ukraine.
President Putin said that he wanted to "discuss the nuances that have developed" over the conflict in Ukraine with Mr Orban, who visited Kyiv earlier this week.
European Union leaders piled on Mr Orban, for paying a visit to a leader wanted for war crimes, as word of the trip spread.
This week Hungary took over the EU's rotating presidency.
"Appeasement will not stop President Putin," European Commission President Ursula von der Leyen wrote on X.
"Only unity and determination will pave the path to a comprehensive, just and lasting peace in Ukraine."
EU foreign policy chief Josep Borrell said in a statement that Mr Orban's "visit to Moscow takes place, exclusively, in the framework of the bilateral relations between Hungary and Russia".
"Prime Minister Orban has not received any mandate from the EU Council to visit Moscow," he added.
The 27-nation EU has firmly opposed Russia's military offensive in Ukraine, imposing 14 rounds of unprecedented sanctions on Moscow.
"That position excludes official contacts between the EU and President Putin. The Hungarian Prime Minister is thus not representing the EU in any form," Mr Borrell said.
"It is worth recalling that President Putin has been indicted by the International Criminal Court and an arrest warrant released for his role in relation to the forced deportation of children from Ukraine to Russia."
EU Council chief Charles Michel had earlier reiterated the common stance that "no discussions about Ukraine can take place without Ukraine".
Hungary's six-month EU presidency gives the central European country sway over the bloc's agenda and priorities for the next six months.
Mr Orban's visit to Moscow comes days after the right-wing nationalist made a surprise trip to Kyiv, where he urged Ukraine's leadership to work towards a rapid ceasefire with Russia.
The Hungarian leader insisted that peace cannot be achieved without dialogue.
"If we just sit in Brussels, we won't be able to get any closer to peace. Action must be taken," Mr Orban said during his regular interview on Hungarian state radio when asked about his visit to Ukraine.
Polish Prime Minister Donald Tusk expressed disbelief at Mr Orban's Moscow trip, while Finnish Prime Minister Petteri Orpo called it "disturbing news".
The visit is the first to Moscow by a European leader since a visit by Austrian Chancellor Karl Nehammer in April 2022.
