Romanian President Traian Basescu narrowly won re-election, final results showed yesterday, but the leftist opposition said it had proof of fraud and would contest the official tally.
Mr Basescu won 50.3 per cent versus 49.7 for Social Democrat leader Mircea Geoana, a razor-thin margin likely to deepen a political schism in the EU newcomer that has paralysed reforms and delayed a €20 billion IMF-led aid deal.
Mr Geoana, who claimed victory as soon as Sunday's voting ended, did not concede defeat, although his designated candidate for prime minister, Klaus Johannis, appeared to accept the outcome, telling a news conference: "My road ends here."
The ex-communist Social Democrats said initial exit polls showing Mr Geoana had won, a large number of annulled ballots and evidence of multiple voting would "obviously force us to contest the result".
"We have proof of fraud," party vice-president Liviu Dragnea told a news conference. Police reported 194 irregularities.
OSCE election observers said the second round of voting met commitments to the pan-European watchdog but urged authorities to investigate reports of irregularities.
The vote was one of the most important for the Balkan state since Stalinist dictator Nicolae Ceausescu was toppled and shot 20 years ago. The victor must name a new government that can restart talks on a stalled International Monetary Fund rescue.
The outcome sent the leu currency slightly lower, and analysts said it illustrated the polarising debate over reforms to boost the economy and wipe out graft in a country ranked the European Union's second poorest and most corrupt.
Mr Basescu thanked his supporters in a brief appearance yesterday and said he would make an official statement after the central election bureau validates the results today.
"The conduct of the second round confirms our initial assessment that this election was held generally in line with OSCE commitments," said Vadim Zhdanovic, head of the Organisation for Security and Cooperation in Europe mission.
"But reports of irregularities should be investigated without delay," he added.
Election officials said they had not received any official complaints contesting the vote. Full results are expected to be validated later this week by the Constitutional Court.
Analysts said the abrasive Mr Basescu may struggle to form a government with other major parties with which he repeatedly clashed over anti-corruption measures during his five-year term.
Mr Basescu, who had trailed Mr Geoana by eight percentage points in the last two opinion polls, owed his victory to winning more than three-quarters of 148,000 ballots cast by Romanians living abroad, who had backed him heavily in a November 22 first round.
At home, ordinary Romanians braced for more turmoil.
"I voted for Basescu, but I think he will continue to fight with other parties," said Daniel Burst, a 42-year-old guard.
Last month, the IMF suspended a review of the aid deal after opposition parties toppled a Basescu-allied Cabinet that has stayed in place as an interim administration.