The Hungarian premier's visits to Moscow and Beijing over the past two weeks have drawn wide condemnation.
Ukrainian President Volodymyr Zelenskyy on Thursday sharply condemned Viktor Orbán's self-styled "peace mission" trips to Moscow and Beijing, suggesting other European leaders should turn their backs to him.
Speaking at the opening of the European Political Community summit at Blenheim Palace in southern England, Zelenskyy warned the other 46 European leaders in attendance that Russian President Vladimir Putin "may approach you" in a bid "to tempt or pressure you, to blackmail you, so that one of you betrays the rest".
The Ukrainian leader did not name his Hungarian counterpart during his 10-minute address, but his remarks made it clear who he was targeting.
"If someone in Europe tries to resolve issues behind others’ backs or even at the expense of someone else, if someone wants to make some trips to the capital of war, to talk and perhaps promise something against our common interests or at the expense of Ukraine or other countries, then why should we consider such a person?
"The EU and NATO can also address all their issues without this one individual."
The summit in the UK comes two weeks after Orbán, then just days into his six-month rotating presidency of the Council of the EU, travelled to Moscow for talks with Putin about the war in Ukraine. He then jetted to Beijing for similar talks with President Xi Jinping.
The trips, which Orbán declared a "peace mission", drew strong condemnation from other EU leaders, none of whom have met with Putin since April 2022 due to his unprovoked full-scale invasion of Ukraine.
The Hungarian government insisted the trips were done on a purely bilateral basis and that Orbán did not represent the bloc, but his use of the Hungarian EU presidency logo left some ambiguity.
The European Commission earlier this week announced its commissioners would boycott informal Council meetings organised by the Hungarian presidency and send senior civil servants instead.
Ursula von der Leyen, the Commission chief who secured a second five-year term at the helm of the EU executive on Thursday, also took aim at Orbán in her speech in front of parliament, describing his controversial trips as "nothing but an appeasement mission".
European Council President Charles Michel, who attended the Blenheim Palace summit on Thursday, told Euronews that "the atmosphere in the room was very respectful".
"I could tell you that those who took the floor, they were very clear about the determination to support Ukraine for as long as it takes."
Michel also reiterated that "the rotating presidency doesn't represent the EU in foreign affairs" and that "the EU has a very clear position" to support Ukraine "for as long as it takes".
Irish Taoiseach Simon Harris also stressed to reporters that the European Council "is absolutely united" in its support for Ukraine.
"I think President Zelenskyy today would have vocalised in his opening remarks perhaps his own views in relation to those issues," he added. "But I share those views. I mean, there is currently a war on the continent of Europe.
"It is more important than ever that Europe speaks with one voice, in terms of defending democracy, sovereignty and territorial integrity."
Orbán reiterated upon arriving at the summit that he had represented only himself, and not the EU, during his trips to the Russian and Chinese capitals.
"That's called political leadership," he said.
Asked about the condemnation he has received, Orbán said other European countries "are more pro-war" than his own.
"They believe that they can destroy militarily the Russians. I don't think so, because I think that there is no solution of this conflict on the battlefield. They hope so, but I don't believe at all because I know the Russians, I know the Soviet Union, I know the Ukrainians, I'm belonging to a neighbouring country.
"(The) solution is not on the battlefield. (The) solution is a negotiation table. Ceasefire negotiation table. But that's what I try to convince them. But, you know, it takes time."