UPDATE 1-Pre-election Iranian poll showed Ahmadinejad support

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WASHINGTON, June 15 (Reuters) - A poll of Iran's electorate three weeks before its election showed President Mahmoud Ahmadinejad leading by a 2-to-1 ratio, greater than the announced results of the contested vote, the pollsters said on Monday.

The poll showed Ahmadinejad's disputed victory, which has sparked riots and demonstrations since it was announced, might reflect the will of the people and "is not the product of widespread fraud," pollsters Ken Ballen and Patrick Doherty said in a column in The Washington Post.

The election protests have marked the sharpest display of discontent in the Islamic republic in years as supporters of opposition candidate Mirhossein Mousavi alleged fraud in Friday's election.

"While Western news reports from Tehran in the days leading up to the voting portrayed an Iranian public enthusiastic about Ahmadinejad's principal opponent ... our scientific sampling from across all 30 of Iran's provinces showed Ahmadinejad well ahead," the pollsters said.

Thirty-four percent of those polled said they would vote for Ahmadinejad while 14 percent preferred Mousavi and 27 percent were undecided.

The poll was conducted by their nonprofit organizations -- Terror Free Tomorrow: The Center for Public Opinion and the American Strategy Program at the New America Foundation -- from May 11 to 20 and funded by the Rockefeller Brothers Fund.

It was the third in a series of polls over the past two years and consisted of 1,001 telephone interviews in Farsi from a neighboring country, with a 3.1 percent margin of error.

"The breadth of Ahmadinejad's support was apparent in our pre-election survey," the pollsters said, rejecting arguments the poll might have reflected a fearful reluctance to give honest answers.