Serbia's security agency warned President Aleksandar Vucic not to travel to Montenegro for Friday's EU-Western Balkans summit, citing security threats amid growing tensions between the two neighboring countries.
Serbia's Security Information Agency (BIA) said late Wednesday that a trip to Montenegro posed a high security risk due to the alleged activities of foreign intelligence services and the presence of organized crime groups.
"The trip to Montenegro is a high security risk due to hostile activities of foreign secret services and the presence of a criminal clan there," the agency said in a statement.
Despite the warning, Serbian Parliament Speaker Ana Brnabic said Vucic intends to attend the summit in the coastal town of Tivat.
Brnabic said she had urged the president to reconsider the trip but that he had rejected the suggestion.
She said that Vucic planned to travel to Tivat despite the warning and that he would have some important meetings there.
"I tried to talk to him about giving up the trip to Tivat, but he does not even want to hear about it," she said, according to Serbian media.
Brnabic added that Vucic would likely travel with a significantly reduced security detail.
"I think people should know that President Vucic will travel tomorrow with minimal security. I don't think more than seven people from his security will be able to travel with him," she said.
The security warning came after Montenegrin authorities prevented a group of 87 men from Serbia from entering the country ahead of the summit.
Police in Tivat said the group was denied entry after arriving on a flight from Belgrade because authorities assessed that they could pose a threat to national security and public order.
Montenegro's police directorate and national security agency said officers discovered a maritime radio device, a banner bearing the slogan of Serbia's ruling party and indications that several members of the group had attended pro-government rallies in Serbia.
"These are persons who attended numerous public gatherings of high security risk," the agencies said in a joint statement.
Authorities added that some of the individuals had violent criminal records.
Police said the operation formed part of broader efforts to prevent "every form of malign activity," including potential destabilization attempts linked to foreign actors seeking to undermine Montenegro's stability and European integration process.
Montenegrin media also reported that police seized two buses intended to transport the group.
Relations between Serbia and Montenegro have remained tense in recent years over Podgorica's relations with Kosovo, which Belgrade does not recognize, as well as allegations of Serbian influence in Montenegro's domestic politics through political and religious networks linked to Serbia.
Montenegro, a NATO member since 2017, has aligned its foreign policy with the European Union, including imposing sanctions on Russia following the invasion of Ukraine, while Serbia has maintained close ties with Moscow.
Serbian broadcaster N1 reported that Belgrade introduced stricter controls at its border with Montenegro on Wednesday evening, causing long delays at crossing points.
The developments come ahead of the EU-Western Balkans summit in Tivat, where European leaders are expected to discuss enlargement and regional cooperation.
French President Emmanuel Macron, German Chancellor Friedrich Merz and European Commission President Ursula von der Leyen are expected to attend the gathering alongside leaders from the six Western Balkan partners.
Serbia, which officially seeks EU membership, has faced increasing criticism from Brussels over democratic backsliding and its continued close relationship with Russia.
The summit also comes as Vucic's government continues to face anti-government protests that have persisted for more than a year, accompanied by growing reports of clashes between demonstrators and government supporters.