Croatian President Zoran Milanović on Monday canceled a key Western Balkans summit scheduled for May, citing statements by Serbia’s leadership that he said risk undermining regional stability.

The Brdo-Brijuni annual summits bring together the presidents of Croatia, Slovenia, Albania, Bosnia-Herzegovina, Kosovo, Montenegro, North Macedonia and Serbia.

The summit was launched by European Union members Croatia and Slovenia in 2013, aiming to improve cooperation between the countries and accelerate their EU integration.

But Milanovic said in a statement that Serbian President Aleksandar Vucic could not visit Croatia and canceled the meeting.

Vucic's political actions in "recent days and weeks ... undermine interstate relations, and threaten peace and stability in Southeast Europe", the statement said.

"Under such circumstances conditions do not exist for, nor is it possible for Vucic to visit Croatia."

He added that the next summit will be held when conditions are met and after consultations with his Slovenian counterpart, Natasa Pirc-Musar.

Milanovic did not elaborate on the statements by his Serbian counterpart that he had been referring to.

Vucic has reacted promptly, saying he "fully supports Zoran Milanovic."

"He is absolutely right, I don't belong there," Serbian public broadcaster RTS quoted Vucic as saying to Tanjug news agency.

Asked if Milanovic's decision is due to his comments over Pristina, Zagreb, Tirana "military aliance," Vucic said "that they do not feel comfortable about it."

The Serbian president has repeatedly accused Albania, Croatia and Kosovo, which signed a defence and security cooperation declaration in March 2025, of forging a "military alliance" against Serbia.

Earlier this month, while commenting on Serbia's possession of Chinese cruise missiles, he said the three nations were waiting for a larger global conflict to launch an attack against Serbia.

Serbia is preparing for their attack, he told Serbian state-run RTS broadcaster.

Earlier Monday, Vucic said that during a call with Russian President Vladimir Putin, he informed him about the "alliance of Zagreb, Pristina and Tirana."

Serbia-Croatia ties have been frosty since Croatia's 1990s war of independence, during which Serbia politically and militarily backed rebel ethnic Serbs.