• Ukraine's president, Volodymr Zelenskyy, on Thursday hit out at European leaders who "betray" Kyiv's interests in a thinly veiled attack against Hungarian Prime Minister Viktor Orban.
• Orban, a Putin ally, has attempted to conduct shadow peace talks during recent visits to Moscow and Kyiv.
• "If someone in Europe tries to resolve issues behind others' backs ... then why should we consider such a person?" Zelenskyy said.

OXFORD, England — Ukraine's president, Volodymr Zelenskyy, on Thursday hit out at European leaders who "betray" Kyiv's interests in a thinly veiled attack against Hungarian Prime Minister Viktor Orban and his shadow peace talks.

Zelenskyy told European leaders that Russia's president, Vladimir Putin, had so far failed to sow disunity within the region, but noted that EU member states — and one weak link in particular — could yet bow to temptation or blackmail.

"He [Putin] may try to approach you or go to some of your partners individually, trying to tempt or pressure you, to blackmail you so that one of you betrays the rest, weakening our unity," he said in opening remarks at the European Political Community summit at Blenheim Palace, England.

The Ukrainian leader said that it was down to individual leaders to decide how to act and "what legacy to leave."

But, in an apparent reference to Orban's recent meeting with Putin in Moscow, he noted that those who act against the Continent's interests should not be considered part of group matters.

"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 promise something against our common interests — or the expense of Ukraine and other countries — then why should we consider such a person?" he said.

"The EU and NATO can also address all their issues without this one individual," he said.

"Putin cannot sustain relationships with truly strong leaders. This is our advantage but it remains our advantage only as long as we are united," he added.

Hungary's Foreign Ministry did not immediately respond to a CNBC request for comment on the remarks.

Zelenskyy was addressing the European Union's 27 member states, as well as 20 other heads of state from across the region, during opening remarks at the European Political Community summit, which was established in 2022 following Russia's invasion of Ukraine.

Last month, Ukraine held its own peace summit with assistance from Switzerland, and Zelenskyy said it is in the process of planning another for later this year.

Orban, an ally of Putin, met with the Russian leader earlier this month, in a trip which drew condemnation from Europe, coming just days after his visit to Kyiv.

Hungary, which is both a member of the EU and NATO, took over the rotating EU presidency earlier this year.

"The peace mission continues. Second stop: Moscow," he said in a social media post at the time.

Speaking to CNBC outside the summit Thursday, Orban said he believed it was his job to convince leaders to "shift from the pro-war policy to a pro-peace policy." In separate comments to reporters, Orban said his sentiments were shared by Republican presidential nominee Donald Trump.

Recalling a meeting last week at Trump's Mar-a-Lago club in Florida, which he at the time dubbed "peace mission 5.0," the Hungarian prime minister said Trump had indicated he would immediately do "everything in favor of peace" if elected in November.

He added that Trump had suggested that the "financial burden" between the U.S. and Europe would be different if he were back in power. "We should understand it here," Orban said ahead of the EPC talks.