French NATO troops fired warning shots and a shock grenade Tuesday to stave off stone-hurling Serbs in a northern Kosovo town where clashes between Serb demonstrators and international forces a day before killed a Ukrainian policeman and left dozens injured.

A police spokesman said the Ukrainian died of injuries suffered from a hand grenade thrown during Monday's clashes in the Serb-controlled town of Kosovska Mitrovica — the worst violence in Kosovo since it declared independence from Serbia a month ago.

Serb demonstrators had attacked international peacekeepers with rocks, hand grenades and Molotov cocktails on Monday as U.N. police were removing protesters from inside a U.N. courthouse. The two sides traded gunfire, leaving more than 60 U.N. and NATO forces and 70 protesters injured.

A Serb demonstrator was in a coma after being shot in the head. The U.N. in Kosovo said Tuesday another 41 policemen were still being treated for injuries.

Tensions remained high in Mitrovica, a town divided between rival ethnic Albanians and Kosovo Serbs who along with Belgrade insist Kosovo's independence is illegal.

French NATO troops used a shock grenade and fired warning shots into the air when a group of high-school students hurled stones at their passing motorcade near one of the Ibar River bridges that divides the town. No one was hurt in the incident.

The Ukrainian policeman who died had been part of special police units that pulled Serb protesters out of the courthouse they had been occupying since Friday to protest Kosovo's Feb. 17 declaration of independence.

He was the first policeman killed in such violent clashes in Kosovo since 1999, when the U.N. took control of the territory from Serbia after a NATO air war halted a Serb crackdown against ethnic Albanian separatists.

NATO troops remained in the town, but the U.N. said Monday it was pulling out of the Serb-dominated part of Mitrovica, Kosovo's second-largest city and a hub for Kosovo's Serb minority — which overall occupies about 15 percent of the territory in northern Kosovo.

The U.N. withdrawal could fuel Kosovo Serbs' desire to split from largely ethnic Albanian Kosovo and rejoin Serbia, which considers Kosovo part of its historic and religious heartland. Serbia has criticized Western countries who have recognized Kosovo's statehood.

Serbia's minister for Kosovo has urged protesters to be patient in realizing their goal of bringing the territory back into the fold — indicating Belgrade may be orchestrating the protests.

"We will protect you just like we protect the Serbs in Serbia," Slobodan Samardzic said Monday. "We will reach the goal only if we are patient, smart and organized and if we believe in what we want to accomplish."

Kosovo's Prime Minister Hashim Thaci said he regretted that Kosovo's minority Serbs were allowing themselves "to be manipulated by Belgrade" into engaging in violence, and vowed: "There will be no compromise with hooligans."

Monday's was not the first protest over Kosovo to turn violent. In Serbia just days after Kosovo declared independence, protesters stormed the U.S. Embassy and set part of it on fire. The body of a Serb student was found in the charred building — the result of a tragic accident, officials said at the time.

U.N. Secretary-General Ban Ki-moon condemned the Kosovo violence on Monday and pledged that the U.N. would continue in its mandate to administer Kosovo, spokeswoman Michele Montas said.

Russia's U.N. Ambassador Vitaly Churkin, whose country has close ties to Serbia and also rejects Kosovo's statehood, expressed "serious misgivings" about the decision by U.N. police and NATO troops to storm the courthouse.

"Even if the takeover by the Serbs of the courthouse was unfortunate ... to us there are some very serious questions involved about the wisdom of such actions and lack of restraint," Churkin said.

Serbian President Boris Tadic accused international forces in Kosovo of "using excessive force," and warned of "escalation of clashes in the entire territory."