Opposition leader Tomislav Nikolic has declared himself the winner in Serbia's runoff election for president in a vote that could boost fears of a renewed nationalism and deepen political divides.
His two-term presidential opponent, Boris Tadic, conceded defeat at his Democratic Party's headquarters amid reports of a low turnout of around 46 percent.
Pollsters at the Center for Free Elections and Democracy (CESID) were projecting Nikolic had won 49.8 percent of the vote to Tadic's 47 percent.
"There is divine justice," a victorious Nikolic told reporters at his Serbian Progressive Party headquarters late on election night, according to RFE/RL's Balkan Service.
A onetime ally of the late Serbian strongman Slobodan Milosevic who more recently abandoned his opposition to European Union membership, Nikolic vowed to supporters that Serbia "will not stray from its European path."
PHOTO GALLERY: Scenes of celebration in Serbia
He said his priorities would be to crack down on crime and corruption, two problems that loomed large in his campaign to defeat his longtime incumbent rival.
"This was not a referendum for or against the EU but to resolve internal problems that were created by Tadic and the Democratic Party," Nikolic said, according to Reuters. "We must start to work, to rid ourselves of crime, to solve the political oligarchy and seek friends the whole world over."
Follow the RFE/RL Balkan Service's continuing coverage of the vote (in Serbian)
Tadic is regarded as a solidly pro-European politician whose Democratic Party is poised to lead the next government after concurrent parliamentary elections two weeks ago weakened it but left the party with a plurality.
His candidacy faced a challenge with voters frustrated at economic stagnation that has left nearly one in four job seekers unemployed.
Tadic appealed "to all political factors to preserve Serbia's strategic orientation towards the EU" in his concession message.
Authorities had said official preliminary results were likely to emerge on May 21 or 22.
WATCH: Two-term President Boris Tadic and challenger Tomislav Nikolic cast their ballots in Belgrade on May 20. (Video by RFE/RL Balkan Service correspondent Iva Martinovic):
Tadic finished just ahead of Nikolic in the first round of voting two weeks ago, then secured the backing of the Socialist Party, the third-largest bloc in the Serbian parliament.
Nikolic's Serbian Progressive Party had threatened to confiscate ballot boxes and close polling stations if its members observed irregularities in the May 20 voting after alleging fraud in the first round.
Tadic's Democrats and Nikolic's Progressive Party finished neck-and-neck in the parliamentary voting that accompanied that first round, at 24 and 22.3 percent, respectively.
Nikolic has said he would pursue EU membership but not at any cost -- suggesting that he could maintain Serbia's claim on the former UN-administered province of Kosovo, which declared independence in 2008.
The European Union made Serbia, which has a population of more than 7 million, an official candidate for membership in March. The union has said that a date for talks could be set early next year if Belgrade takes steps to improve relations with Kosovo, which it does not recognize as an independent state.
Analysts suggested to RFE/RL's Balkan Service that a lack of choice contributed to the low turnout. Tadic had defeated the second-place Nikolic in each of Serbia's last two presidential elections, in 2004 and 2008.
In both those elections, Nikolic stood as the candidate of the Serbian Radical Party, which he helped found but left in October 2008.
The latest vote is for a five-year term in a system that places greater power in the hands of the prime minister but leaves influence and opportunity to slow or block legislation in the office of the president.
Written by Andy Heil based on reporting by RFE/RL's Balkan Service; with additional Reuters and AP reporting