Serbian president Boris Tadic claimed victory in the parliamentary elections on behalf of the pro-Western coalition of parties headlined by his own Democrats (DS), claiming that it would form the next government after the snap polls held on May 11.

With one third of the votes counted, the DS coalition was in the lead with 36.7 per cent, or 102 seats in the 250-seat assembly. Its biggest rival, the Radicals (SRS), who advocate cutting all ties with the European Union over the recognition of Kosovo by the majority of the bloc's countries, was second with 28.6 per cent and 80 seats, data from the electoral commission showed, as quoted by private broadcaster B92.

The coalition would "lead the country to the EU and fight to preserve Kosovo," Tadić told reporters at his party headquarters. "These are the two goals that the new government and I as president will work for."

SRS leader Tomislav Nikolic, who narrowly lost the presidential election to Tadic earlier this year, refused to concede defeat. "There exist very clear possibilities of a coalition which does not include the Democratic Party," he said in his first reaction to the election result, as quoted by Reuters.

Nikolic said he would seek talks with the Democratic Party of Serbia (DSS) of outgoing prime minister Vojislav Kostunica, who shares SRS's position for closer ties with Russia and staying away from the EU unless the bloc treats Kosovo as an integral part of Serbia.

Kostunica's falling out with DS and its allies on the Kosovo issue was the reason the elections were called in the first place and an alliance with the DS appeared highly unlikely. DSS is projected to win 37 seats, having received 13.5 per cent of all votes.

The biggests surprise was the showing of the Socialist party (SPS), founded by the late Slobodan Milosevic, which is set to win 25 seats and play kingmaker in the next government, pundits in Belgrade said.

"The SPS will decide who puts together the new cabinet," analyst Slobodan Antonić said, as quoted by B92. SPS's negotiating position was "tricky, since their voters are closer to the DSS-NS coalition and the Radicals", although the party "could stand to gain more" if it joined the DS coalition.

Another obstacle was that should the small Liberal Democrat party (LDP) make it into parliament, it would join the DS coalition. With 33.9 per cent of all votes counted, it had received only 4.6 per cent, just short of the five per cent threshold to enter parliament, according to the data of the electoral commission.

Exit polls from the non-governmental Centre for Free Elections and Democracy (CeSID), however, projected it would gain 5.2 per cent and win 13 seats. "The problem is that the LDP is 'added' to the DS-led coalition, while the LDP and SPS have huge differences among them," Antonić said, as quoted by B92.

Election authorities will release updated vote count figures later in the day, with the final results to be announced on May 15, Tanjug news agency reported. Turnout was 62.5 per cent, the agency said, quoting the electoral commission.

The EU, which offered Serbia pre-membership and visa facilitation deals in the weeks before the vote, will welcome the result, but also hope that the pro-Western coalition will conclude negotiations on the new government as soon as possible.

"The pro-European side in Serbia won, which was what we were aiming for in the European Union," Slovenian Foreign Minister Dimitrij Rupel told Reuters in a telephone interview. Slovenia holds the rotating presidency of the bloc.