The U.N. war crimes tribunal cleared Kosovo's former prime minister on Thursday of persecuting Serbs in a 1998-99 separatist war, a move expected to fan tensions simmering over Kosovo's secession.

Ramush Haradinaj, a former commander of the Kosovo Liberation Army (KLA) considered a hero by Kosovo Albanians, was acquitted of torture, murder, rape and deportation after judges found prosecutors had failed to prove a deliberate campaign to kill and expel Serb civilians from Kosovo.

"This is a verdict that strengthens Kosovo. We endured a difficult liberation struggle that cost many lives. Today we are a free and sovereign nation," Haradinaj said in a statement, adding he would dedicate his life to equal opportunities to all.

Kosovo's 90 percent Albanian majority declared independence from Serbia in February. The United Nations has run the province since 1999 when NATO drove out Serb forces to halt the ethnic cleansing of Albanians in a two-year war against KLA guerrillas.

Serbia's government collapsed Saturday over an impasse between the nationalist prime minister and the pro-Western president on how Kosovo's independence affects the Balkan country's pursuit of EU membership.

''The government, which does not have united policies, cannot function,'' Prime Minister Vojislav Kostunica said as he announced the fall of his Cabinet. ''That's the end of the government.''

Kostunica said he will convene a session of the caretaker government Monday, which will propose to President Boris Tadic to dissolve the Parliament and call new elections for May 11.

Tadic said in a statement that he will call early elections because they are a ''democratic way to overcome the political crisis.''

But he disputed Kostunica's claim that their clash was over Kosovo, the Serbian medieval heartland which proclaimed independence last month with the backing of the United States and several EU countries.

Kosovo's parliament has unanimously endorsed a declaration of independence from Serbia, in a historic session.

Celebrations went on into the night after Prime Minister Hashim Thaci promised a democracy that respected the rights of all ethnic communities.