Hundreds of hardline Serb nationalists and pro-Russia activists rallied in downtown Belgrade, threatening riots if Serbia accepts a Western-backed plan aimed at mending ties with Kosovo, its former mainly Albanian southern province.
Pro-Russian sentiment is running high in Serbia which regards Russia, a veto-wielding member of the U.N. Security Council, as a main ally in its opposition to the 15-year-old independence of Kosovo.
Protesters, carrying posters reading "Kosovo-No Surrender", cheered "Serbia-Russia" when ultranationalist Damjan Knezevic called for rioting if Belgrade seeks to improve ties with Kosovo.
"You (government) are fearing riots. I swear to you, we are ready for more than that," said Knezevic, whose People's Patrol supports Russia's invasion of Ukraine and is active in the persecution of migrants at home.
Knezevic admits ties with Russia's Wagner mercenary group which is fighting in Ukraine.
After the protest, President Aleksandar Vucic, who is balancing between Serbia's EU ambitions and ties with Russia, said he was not sure whether protesters "were pro-Russian," but that he was sure "they were anti-Serbian."
"All who threatened with murders and beatings will answer to Serbian laws," he said in a TV broadcast after meeting chiefs of state security and law enforcement bodies.
Earlier in the day, police said two supporters of Knezevic's organisation heading to the rally had been detained in the north of the country and that a sniper rifle and ammunition had been found in their car.
"If our state leadership ... fails to prevent Kosovo from joining the U.N., we are asking the Russian leadership to use its veto and to give us at least a month to remove this traitor," Knezevic told the cheering crowd, referring to Vucic.
Although it has repeatedly condemned Russia's invasion of Ukraine in the United Nations and other international forums, Serbia has been criticised by the West for not formally introducing sanctions against Moscow.
On Friday, Prime Minister Ana Brnabic said that the level of Serbia's alignment with common foreign and defence policies of the EU including the introduction of sanctions to Russia "is a condition above all conditions" for joining the bloc.
Last December, Vucic said Serbia had clamped down on those who attempted to bypass sanctions against Russia through Serbia and in January he criticised efforts by the Wagner group to recruit mercenaries from the country.
(Reporting by Aleksandar Vasovic; Editing by Nick Macfie and Alistair Bell)
