BELGRADE, Serbia - Serbs scattered their votes among 20 political parties in parliamentary elections, leaving no group with enough power to rule alone, according to official partial returns released Monday in a troubled Balkan nation divided over Western-style reforms and the future of Kosovo.

The vote was the first since Serbia became independent last year with the end to its union with Montenegro, its last partner from the former Yugoslav federation. Soon after the vote, the U.N. was expected to propose a plan for the future of Serbia's breakaway Kosovo province.

Voters chose from parties ranging from ultranationalists and conservatives to pro-Western reformists and liberals. Parties needed a minimum 5 percent of the total vote to earn a place in the 250-member parliament.

The Serbian Radical Party, loyal to late ex-leader Slobodan Milosevic and opposed to Serbia's EU membership at the expense of Kosovo's independence, won 28.3 percent of the vote. But that was not enough for the party to govern alone, the state electoral commission said.

The Western-backed Democratic Party of President Boris Tadic was second with 22.6 percent, and the center-right Popular Coalition led by Prime Minister Vojislav Kostunica had 16.3 percent, according to the official results with about 70 percent of the vote counted.

Turnout was 62 percent, the state electoral commission said, indicating strong interest among the 6.6 million-member electorate.

Challenges facing the next parliament and government include Western demands for the arrest of war crimes fugitive Ratko Mladic and the dispute over Kosovo, where a predominantly ethnic Albanian population seeks independence over the strong opposition of most Serbs.

Serbia's bickering pro-democratic parties could partner to form a governing coalition if they agree on who will be the next prime minister. Kostunica has insisted on retaining the post while the Democrats want to have one of their own in the office.

"The Serbian Radical Party is the winner ... but we will not have the opportunity to form the government," party leader Tomislav Nikolic said.

Kostunica was noncommittal about whether he would step down and allow a Democrat to take his place.

"The question who is going with whom is inappropriate at this moment," Kostunica said. "The president will have to find a man who will be able to get a majority" in the parliament.

In campaigning, Kostunica navigated a central course, advocating EU integration but refusing to denounce Milosevic-era parties. He has pursued Western-advised reforms but failed to arrest Mladic.

Tadic pledged that a government led by his Democrats would work harder to arrest the fugitive, indicted by the U.N. war crimes tribunal for a massacre of thousands of Bosnian Muslims during the 1992-95 war there.

The election came a day before talks between EU foreign ministers in Brussels, Belgium, with Kosovo at the top of the agenda. The 27-nation bloc will look closely at the election results, hoping pro-Western parties will have enough strength to push ahead with democratic and economic reforms and fully cooperate with the U.N. war crimes tribunal in The Hague, Netherlands.

On Friday, U.N. envoy Martti Ahtisaari is expected to present a proposal that will include some sort of conditional independence for the province, which has been an international protectorate since the 1998-99 war between Milosevic's troops and separatist ethnic Albanians.

Tadic and Kostunica have lobbied internationally to keep Kosovo within Serbia, offering broad autonomy to the ethnic Albanians. The two pledged to resolve the Kosovo crisis peacefully, a promise the Radicals refused to make.