"A Ukrainian police officer serving with the UN police died overnight of injuries sustained to the stomach," Alexander Ivanko said.
He also added that, "Forty-two UN policemen and 22 Kosovo Force [KFOR] soldiers were wounded in the town of Mitrovica."
The violence in the Serb-dominated area of Mitrovica began when UN police and NATO-led KFOR troops launched an operation on Monday morning to regain control of a UN court building seized last week by ethnic Serbs.
Serb rioters attacked UN forces with rocks, grenades and Molotov cocktails as they removed the protesters from inside the courthouse.
According to the latest reports, over 100 Serbs were also wounded in the worst outbreak of violence in the region since Kosovo declared independence on February 17.
"There are some people with serious injuries, but most civilians sustained minor injuries," Ivanko said. "The worst injuries were caused by automatic gunfire and grenade explosions."
Unconfirmed reports say a Serb is in intensive care after being shot in the head.
The spokesman also said the situation in Mitrovica had now stabilized, and that UN police could soon return to the town.
The UN mission was forced to withdraw its police and civilian staff from the Serb stronghold in northern Kosovo at the height of the violence. Kosovo has been a UN protectorate since a 1999 NATO bombing campaign of Belgrade ended a conflict between Serbs and ethnic Albanians in the area.
Meanwhile, Ukrainian Interior Minister Yuriy Lutsenko may visit Kosovo to inspect the country's peacekeeping contingent, a ministry spokesman said on Tuesday.
Ukraine has contributed 155 police and 182 military personnel to the UN police and NATO-led KFOR in Kosovo. More than 20 Ukrainian policemen were wounded in Monday's violence.
Serbia, backed by its ally Russia, has categorically rejected independence for Kosovo. China, with its own separatist problems, most notably in Tibet, has also refused to recognize "the world's newest state."
Kosovo's independence has so far been recognized by the United States, the majority of EU countries, and a number of other countries.
