Serbian President Boris Tadic is appealing for diplomacy after Kosovo police tried to seize control of two border posts in Kosovo's Serb-dominated north, wounding two officers and three civilians.

Mr. Tadic said Tuesday the police action was intended to take over Serb areas and is completely unacceptable. He warned any outsiders who would encourage the Kosovo police that they would be making a terrible mistake and put the Balkans at risk.

Kosovo police forces tried to take over the Brnjak and Jarinje crossings on the Serbian border late Monday. Their action triggered fighting with Serbian protesters. Police and medical officials say one Kosovo officer was shot in the head and a second was wounded by a grenade. Reports say three civilians were also wounded.

NATO peacekeepers are trying restore calm. A European Union spokeswoman says the Kosovo police did not consult with the international community first and that the EU does not approve of the action.

A State Department spokeswoman says the United States regrets what happened in Kosovo. It urges Serbs and Kosovars to work urgently to defuse the situation.

Kosovo's ethnic Albanian government wants to assert control over northern regions where local Serbs refuse to recognize its 2008 declaration of independence from Serbia. Kosovo is also trying to enforce a recent ban on Serbian exports.

Serbia banned goods from Kosovo since the 2008 independence. Serbia has said it will never recognize an independent Kosovo, but wants to settle its differences with Kosovo through negotiations.