An analysis by a British think tank highlights profound differences between voting patterns in Iran's recent election and hard-line President Mahmoud Ahmadinejad's first victory in 2005, casting doubt on whether they could have occurred without manipulation.
The analysis by the London-based Chatham House could provide ammunition for supporters of Mir Hossein Mousavi, the pro-reform candidate who claims he was the true winner in the June 12 election.
The dispute has sparked more than a week of unrest in Iran that has killed at least 17 people and presented the regime with its greatest challenge since the 1979 Islamic revolution.
Iran's highest electoral authority acknowledged irregularities in the election for the first time Monday but insisted they did not affect the outcome.
The official results showed that Ahmadinejad received 13 million more votes than he and other conservatives got in the 2005 election, according to the Chatham House report, which was released Sunday.
The results would have required him to receive support in a third of the provinces from all former conservative voters, all former centrist voters, all new voters and almost half of all former reformist voters - an unlikely scenario, said the study.
Discontent with Ahmadinejad was running high among reformists and even some conservatives unhappy with his handling of the economy and his antagonistic stance toward the international community.
The final tally was 62.6 percent of the vote for Ahmadinejad and 33.75 percent for Mousavi - a landslide victory in a race that was perceived to be much closer.
Such a huge margin went against the expectation that a high turnout - a record 85 percent of Iran's 46.2 million eligible voters - would boost Mousavi, whose campaign energized young people to vote. About a third of the eligible voters were under 30.
Ahmadinejad has called the June 12 election "real and free."
The Chatham House report cast doubt on the idea that large numbers of conservative voters who had not voted in previous election might have come out this time to support Ahmadinejad.
While the official results indicate Ahmadinejad increased the conservative vote by 113 percent compared with the 2005 election, there is little correlation at the provincial level between the increase in turnout and the swing to the president.
"This challenges the notion that Ahmadinejad's victory was due to the massive participation of a previously silent conservative majority," said the study.
The research found that turnout in two provinces, Mazandaran and Yazd, was more than 100 percent. The practice of using identity documents of dead people to cast additional ballots is a common and
widespread problem in Iran, said the report.
The Guardian Council, which certifies election results, acknowledged Monday that more votes were cast in 50 districts than there were registered voters.
But this "has no effect on the result of the elections," council spokesman Abbas Ali Kadkhodaei was quoted as saying on the state TV Web site.
International monitors are barred from observing Iranian elections, and Mousavi has charged that representatives of his campaign were expelled from polling centers even though each candidate was allowed one observer at each location.
The Guardian Council, which is closely allied with Iran's Supreme Leader Ayatollah Ali Khamenei, has agreed to recount a sampling of 10 percent of the ballot boxes nationwide. But Mousavi has said he does not believe the council is neutral and has demanded a new election.
Many commentators have pointed to Ahmadinejad's support in rural areas as the reason for his political success. But the study said conservative candidates, particularly Ahmadinejad, were "markedly unpopular" in rural areas in past presidential elections.
Ahmadinejad has campaigned in all of the provinces, but the think tank cast doubt on the 2009 results that showed a sudden shift to the president in rural areas.
"This increase in support for Ahmadinejad amongst rural and ethnic minority voters is out of step with previous trends, extremely large in scale, and central to the question of why (or indeed whether) he won in June 2009," said the study.
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