Serbian authorities on Tuesday detained Kosovo Serb politician Milan Radoicic and accused him of manufacturing firearms and trafficking them to Kosovo,after he said he was involved in a deadly shootout with Kosovo police 10 days ago.

Tensions between Belgrade and Pristina have soared since Sept. 24, when around 30 armed Serbs barricaded themselves in a Serbian Orthodox monastery near the village of Banjska, in the Serb majority north of Kosovo, resulting in a shootout with Kosovo police.

Three attackers and a Kosovo police officer were killed.

The Office of Serbia’s High Public Prosecutor said in a statement that Radoicic was interrogated on Tuesday under suspicion of having joined with others in illegal manufacturing, possession and trafficking of fire arms and explosive materials.

It added Radoicic had allegedly been buying weapons, ammunition and explosive devices in the Bosnian town of Tuzla, to be delivered to Belgrade between January 2023 and September 24.

After delivery, he would transfer and store the weapons in various locations in Kosovo, either in deserted facilities or in the woods, the statement alleged.

On Sept. 24, Radoicic and his group “jeopardised lives of people in Banjska,” the prosecutor said.

Radoicic denied any criminal activity. The prosecutor has asked a court to order Radoicic be kept in detention because he could flee.

Last month’s gunbattle prompted new international concern over stability in Kosovo, which has an ethnic Albanian majority and declared independence from Serbia in 2008 after a guerrilla uprising and a 1999 Nato intervention.

Some 50,000 Serbs who live in north Kosovo do not recognise Pristina’s institutions and see Belgrade as their capital. They have often clashed with Kosovo police and international peacekeepers, but last month’s violence was the worst in years.

Radoicic, vice president of the Serb List party which is dominant in north Kosovo, admitted to taking part in the skirmishes, by saying he had come to Kosovo with the group “to encourage Serb people to resist (Prime Minister Albin) Kurti’s terrorist regime”. He was questioned by Serbian police last week over his remarks.

Radoicic’s lawyer Goran Petronijevic could not be immediately reached for comment.

Pristina authorities had accused Belgrade of providing financial and practical support for the operation, something Serbian authorities denied. Kosovo and Western countries have also accused Serbia of a buildup of military presence in the so-called Ground Safety Zone, a 5 kilometre-wide strip inside Serbia along the Kosovo border.

On Monday, Serbia’s army commander General Milan Mojsilovic said the country has withdrawn some troops.