BELGRADE, Serbia (AP) — A court in Serbia on Wednesday released from a brief detention a Kosovo Serb leader who has been linked to a clash with Kosovo security forces in which four people died, sending tensions soaring in the volatile region.

Milan Radoicic, a politician and wealthy businessman with ties to Serbia’s ruling populist party and President Aleksandar Vucic, was detained in Belgrade on Tuesday. He’s suspected of leading a group of some 30 heavily armed Serb insurgents who on Sept. 24 ambushed and killed a Kosovo policeman, triggering a gunfight in a northern Kosovo village that also left three paramilitaries dead.

Kosovo has accused Serbia of orchestrating the “act of aggression” against its former province whose 2008 declaration of independence Belgrade doesn’t recognize. Serbia has denied this, saying that Radoicic and his group acted on their own.

A Belgrade judge on Wednesday ignored public prosecutor’s call that Radoicic be kept in custody because he could flee, and ruled that he was banned from leaving Serbia. He should also report to the authorities twice a month pending a trial, the judge said.

Kosovo’s Justice Minister Albulena Haxhiu said she is not surprised by Radoicic’s release from custody.

“Serbia has never handed over criminals and will not hand over terrorists either,” Haxhiu said. “To put it plainly, Serbia is a haven for war criminals and terrorists who 10 days ago carried out a terrorist attack on the territory of Kosovo.”

Serbian prosecutors have said Radoicic is suspected of a criminal conspiracy, unlawful possession of weapons and explosives and grave acts against public safety. They said Radoicic got weapons delivered from Bosnia to Belgrade before stashing them in “abandoned objects and forests” in Kosovo.

Radoicic denied the charges although earlier admitting being part of the paramilitary group involved in the gunfight.

Radoicic was a deputy leader of the Serbian List party in Kosovo, which is closely linked with Vucic’s Serbian Progressive Party. He is known to own large properties both in Serbia in Kosovo, and has been linked by investigative media to shady businesses.

European Union and U.S. officials have demanded from Serbia that all the perpetrators of the attack, including Radoicic, be brought to justice. Radoicic, 45, has been under U.S. and British sanctions for his alleged financial criminal activity.

Serbia has said it has withdrawn nearly half of its army troops from the border with Kosovo, after the United States and the EU expressed concern over the reported buildup of men and equipment and threatened sanctions.

The flare-up in tensions between Serbia and Kosovo has fueled fears in the West that the volatile region could spin back into instability that marked the war years in the 1990s, including the 1998-99 war in Kosovo.

That conflict ended with NATO bombing Serbia to stop its onslaught against separatist ethnic Albanians. Belgrade has never agreed to let go of the territory, although it hasn’t had much control over it since 1999.