Partying on the streets may be premature for Serbia's pro-European bloc, with tough talks ahead to see if it can form a government.

Rival runners-up, the hardline nationalists, remain poised for power too, claiming they could also lead a ruling coalition.

The Radicals' leader, Tomislav Nikolic, warned the president's supporters not to jump the gun.
"Boris Tadic does not have the right to present this as a celebration of those who will form the new government," he said, stressing his opponents' failure to secure a parliamentary majority.

A natural partner in a nationalist coalition would be Serbia's outgoing prime minister. Unrelenting in his opposition to Kosovo's Western-backed breakaway, Vojislav Kostunica insists this issue is more important than eventual EU membership. Because of this he pulled out of President Tadic's government in March, prompting early elections. And he said his camp would only participate in a parliamentary majority defending its principles, in comments that appear to rule out any attempt to patch up differences with his former ally.

The key kingmaker could be the Socialists of late strongman Slobodan Milosevic. Analysts say they could join either side.

Parliament must convene by mid-June with a government formed by mid-September. Failing this, Serbia's people will be forced to return to the polls.