BUCHAREST, Romania - Romania's main opposition party claimed yesterday that President Traian Basescu narrowly won reelection through a fraudulent vote.

The Social Democrats said left-leaning former Foreign Minister Mircea Geoana actually won Sunday's runoff, an election seen as crucial to addressing a government crisis and the country's painful recession.

With 99.95 percent of the vote counted, election authorities said centrist Basescu, 58, polled 50.33 percent of the vote, while Geoana, 51, received 49.66 percent.

Liviu Dragnea of the Social Democrats said there were too many voided ballots - a total of 138,000 - more than enough to make up the approximately 70,000 vote difference between the two candidates.

He said that some polling stations altered final documentation and possibly forged ballots sent to central election authorities.

He also cited "massive electoral tourism," referring to the 617,000 voters who cast ballots at special voting centers, many of whom he alleged had already voted elsewhere.

"We contest the election," Dragnea said. "Romanians voted for Mircea Geoana, but Basescu's state apparatus is trying to make him the presidential winner through fraud."

Other leading politicians - including top Liberal Party lawmaker Lucian Orban and former Prime Minister Adrian Nastase, who ran for president against Basescu in 2004 - also noted irregularities.

Basescu dismissed the allegations, saying that if there were a recount, he would win by three percentage points.

He accused the Social Democrats of manipulating exit polls and said the fact that they were contesting the elections was "embarrassing."

Observers from the Organization for Security and Cooperation in Europe said the second round of voting met their standards but urged authorities to investigate reports of irregularities.

Romania faces skyrocketing unemployment and a limping government since the ruling coalition fell apart two months ago amid party squabbling.