German Chancellor Friedrich Merz lashed out at  Viktor Orban during a meeting of European Union (EU) leaders in Copenhagen, Denmark on Wednesday, accusing the Hungarian prime minister of derailing discussions on the bloc’s security needs, Bloomberg reports.

The clash took place during a discussion over how the EU can better defend itself and support Ukraine, according to people familiar with the exchange, who spoke on the condition of anonymity.

The quarrel is the latest sign of EU frustration with Orban, who has wielded his veto to stymie sanctions against Russia and opposes Ukraine’s EU bid. And it comes as the bloc struggles to unite on plans to rebuild its defenses, Bloomberg recalls.