"I am the definite winner of this presidential election," Mousavi told a news conference.
But the Islamic Republic's election commission said Ahmadinejad was ahead with 64.8 percent of the votes from Friday's presidential election in the world's fifth biggest oil exporter after more than 30 million ballots had been counted.
Mousavi had around 32 percent support, said the commission. Based on an Interior Ministry estimate of a maximum 80 percent turnout of Iran's 46 million eligible voters, he could not beat Ahmadinejad with the votes still to be counted.
The official news agency IRNA said: "Dr Ahmadinejad, by winning most votes ... has secured his victory." State media said final results would be announced at 10 a.m. (1:30 a.m. EDT).
Trita Parsi, president of the Washington-based National Iranian American Council, expressed disbelief at the wide margin in Ahmadinejad's favor.
"It is difficult to feel comfortable that this occurred without any cheating," Parsi said. ... Reuters/NYTimes
