* Three Kosovo Serbs and NATO soldier hospitalised
* NATO sends reinforcements to northern Kosovo
* KFOR made a very risky move, says Serb government official (Adds comments from Serb leader)
By Branislav Krstic and Fatos Bytyci
ZVECAN, Kosovo, June 1 (Reuters) - At least three Kosovo Serbs and a NATO soldier were wounded in a gunfight on Friday, as peacekeepers tried to dismantle Serb barricades blocking traffic, a Reuters witness said.
NATO troops in the Kosovo Force (KFOR) fired tear gas and small arms and some protesters fired back with handguns.
The troops, in armoured personnel carriers, were confronted by hundreds of Serbs who pelted them with stones near roadblocks in the villages of Rudare and Dudin Krs outside the town of Zvecan in a Serb-dominated northern area of Kosovo.
The roadblocks are among the last on major roads yet to be dismantled by KFOR. They were erected as part of a long-running Serb campaign to prevent the government of Albanian-majority independent Kosovo from imposing its rule in the area.
"One KFOR soldier has been wounded, has been evacuated and he is stable," said NATO spokesperson in Kosovo Uwe Nowitzki.
"KFOR will not allow the situation to escalate and will use a proportional level of force necessary to maintain a safe and secure environment," Nowitzki said. The operation to remove the roadblocks was continuing, he said.
Kosovo, which declared independence from Serbia in 2008, is 90 percent ethnic Albanian. But Serbs opposed to independence dominate in a small swathe of the north bordering Serbia which continues to function as part of the Serbian state, resisting efforts by the Kosovo government to extend its authority.
A Reuters witness said extra KFOR troops arrived to reinforce the troops from Germany and the United States after the initial clashes and were deployed on hills overlooking Rudare. Several NATO helicopters were also flying over the area.
Dragisa Milovic, the mayor of Zvecan which is about 60 km (40 miles) from the capital Pristina, told Reuters that KFOR had refused to allow Serb medical personnel to help wounded Serbs, and said: "A commander told me they have the authority to use deadly force on anyone who throws a stone or uses a weapon."
Milovic said he had asked Serbs to withdraw to restore calm.
Kosovo Serbs set up barricades at boundary crossings with Serbia last year after authorities in Pristina, the EU's police and judiciary mission EULEX tried to establish their presence.
A Kosovo policeman was killed in an ambush and several civilians and NATO troops were injured in clashes that have erupted over the last few months.
Health authorities in the Serb-controlled north of the city of Mitrovica said three Serbs were hospitalised while others were released after treatment for slight injuries.
Krstimir Pantic, mayor of the Serb-controlled part of the northern city of Mitrovica, said the municipal council and "the people" had decided to warn KFOR and EULEX not to enter the area under Serb control after the latest clashes.
"We have decided to tell them that the (Serb part of) Mitrovica is not open for them ... that we cannot guarantee them safety," Pantic said.
Earlier this year, Belgrade sought to mend ties with Kosovo and agreed to open border crossings and establish cooperation with Pristina on issues like driving licences, land registration and school diplomas to secure European Union candidacy.
The outgoing pro-Western authorities in Belgrade have accused nationalists from the four Serb municipalities in Kosovo's north of stirring up trouble ahead of Serbia's May parliamentary and presidential elections, which ended in a victory for rightist challenger Tomislav Nikolic.
Oliver Ivanovic, Serbia's state secretary for Kosovo in the outgoing government, said KFOR had made "a risky move" by trying to remove the roadblocks and warned the situation in northern Kosovo was "volatile and may escalate by the end of the day".
"I cannot understand what motivated KFOR to make such a move ... except that it had an intention to reinforce Pristina's position ahead of the resumption of talks (with Serbia) this year," he said.
"We are the outgoing government and we can make only limited moves."
Nikolic, a former ultranationalist, took an oath of office on Thursday. He pledged he would maintain Serbia's EU bid, but would never renounce Kosovo as an integral part of Serbia.
Independent Kosovo has been recognised by 90 countries, including the United States and 22 of the EU's 27 member states. (Writing by Aleksandar Vasovic; Editing by Louise Ireland and Andrew Roche)