Belgrade  -  A party once led by strongman Slobodan Milosevic began coalition talks Wednesday with Serbia's caretaker prime minister after emerging as possible kingmaker in weekend elections.

As the swing party in the new parliament, the ex-communist Socialists can determine Serbia's course by supporting either hard- line nationalists or President Boris Tadic's pro-Europe bloc.

Prime Minister Vojislav Kostunica, who has leaned increasingly nationalist since Serbia lost Kosovo, met Socialist leader Ivica Dacic for talks on a new government, but reached no immediate deal.

Dacic, 42, a former top aide to the late Milosevic who has tried to modernize the party, said talks were "constructive" and would continue Thursday. He declined to comment on the possibility of allying with Tadic's Democratic Party, which won the most votes on Sunday's elections.

Tadic is counting on the support of the small, pro-Western Liberal Democrats, but he needs a second ally to build a governing majority in the 250-seat parliament.

Tadic wants to keep Serbia on course to European Union membership, which has been challenged by the ultra-nationalists camp led by Kostunica and the Radical Party. They want to steer the country away from the West in protest at its support of Kosovo's independence.

Kostunica's Democratic Party of Serbia and the ultra-nationalist Serbian Radical Party, the number-two force in parliament, have announced a tentative coalition deal, but they also need a partner for a majority.

That leaves Socialists with their 20 seats in the key role.

Tadic said the Socialists are a "totally acceptable" coalition partner because both parties wanted social reforms, justice and equal opportunities for Serbs.

Bringing the Socialists into a pro-European government would give unexpected legitimacy to the force seen as most responsible for the devastation across former Yugoslavia during the 1990s.

It barely survived Milosevic's fall in 2000 and is now seeking to show a modernized, tolerant face, two years after his death while on trial for war crimes - although it never renounced him.

But the Socialists also hold grudges against Tadic's party and the Liberal Democrats over Milosevic's arrest and handover to the war crimes tribunal in The Hague.

Kostunica and the Radicals seem the more likely partners for the Socialists, who sang Russian songs during election night and whose leader Dacic spoke in Russian at the congress of Vladimir Putin's Unity Party of Russia.

Under Serbian law, the new parliament must convene within a month after the elections and the new government within three months after the constitution of the parliament. (dpa)