Pro-Western Boris Tadic headed for a second term as Serbia's president on Sunday, initial results showed, sparking wild celebrations in Belgrade despite fears over Kosovo's looming independence.

Tadic, who campaigned on European Union-backed prosperity, had 51.1 percent of the vote against 47.2 percent for Tomislav Nikolic, an ultra-nationalist who favours greater links to Russia, said the electoral commission after the run-off vote.

Nikolic, defeated by Tadic in 2004, acknowledged he had probably lost again and Tadic supporters poured onto the streets of the capital, sounding car horns and waving blue and yellow Democratic Party flags as they converged on the downtown area.

The EU's Slovenian presidency congratulated Tadic on his victory in the polls, saying it reflected the democratic resolve to join the bloc.

Slovenian Prime Minister Janez Jansa, whose country currently holds the EU's rotating presidency, "emphasised that the outcome of the Serbian presidential elections should also be understood as the reflection of the wishes and resolve of democratic forces to further Serbia on its path towards membership of the European Union."

Jansa also expressed "his firm belief that Serbia would very soon succeed in meeting the criteria required in order to proceed along this path," the EU presidency statement added.

In Belgrade, fireworks erupted before Tadic appeared at a window overlooking the main Terazije avenue to a cacophony of noise from hundreds of cheering supporters.

"This is Serbia's victory. I think we have proven both to Europe and everywhere else in the world what kind of democracy we have in Serbia," Tadic told them.

"We give support today to our fellow people in Kosovo and show them that we will never let them down," he said.

"We don't want bad things to come to anyone. We want peace, cooperation with all countries in the region, but we demand Serbia be respected, for everyone to respect Serbian people and all the people living in Serbia."

The threat by majority ethnic Albanians in Kosovo to make a unilateral declaration of independence within days of the election has been opposed by both candidates and worried voters.

The Kosovo issue and the fact the two presidential candidates had promised to take the country in very different directions led to the highest turnout since late strongman Slobodan Milosevic was defeated in elections in 2000.

The result is expected to have a bearing on the shaky coalition government made up of Tadic's Democrats and the party of Prime Minister Vojislav Kostunica.

Kostunica had refused to back Tadic because the president would not take a tougher line against EU support for an independent Kosovo.

In Belgrade, a war-weary city so often at the crossroads of the region's turbulent history, voters said they were torn between a future in the EU and losing Kosovo.

PHOTO CAPTION

Serbia's President and Democratic Party leader Boris Tadic addresses media after his headquarter claimed victory in presidential elections.