Kaveh Kahen, an Iranian graduate student who lives in Gaithersburg, debated with himself for weeks. Whom should he vote for in Iran's presidential poll? Should he even vote?

Kahen, 27, ultimately joined a slow but steady trickle of Iranians who turned up yesterday at the Iranian Interests Section in Northwest Washington to cast ballots in Iran's ninth presidential election since its 1979 Islamic revolution.

Kahen said he reasoned that an election boycott, which some Iranians had called for, would only please two groups that he did not want to please: Iranian hard-liners and "neo-cons in the United States."

And though his "pragmatic side" favored former president Ali Akbar Hashemi Rafsanjani, Kahen said he eventually opted for his "idealistic side" and voted for reformist candidate Mostafa Moin, a former education minister.

His friend Amir Togha, 36, who teaches math at George Washington University, also rejected the boycott and chose Moin. "When there is a crack in the wall of tyranny," Togha said, "we have to put a crowbar in the crack."

Iranians 16 and older who showed a birth certificate or valid Iranian passport were given a paper ballot that listed the names of the seven presidential candidates. U.S. citizens of Iranian descent also were allowed to vote.

Afterward, they dipped a finger in purple ink and had their document stamped to prevent double-voting.

Official results were not expected until today. If no candidate receives more than 50 percent of the vote, a runoff will be held between the top two.

Some reformist groups in Iran had called for a vote boycott to protest the involvement of clerics in Iran's political system.

The Bush administration also had criticized the election, noting that Iran's senior clerics barred many reform candidates from running.

About a dozen protesters, carrying signs urging a boycott and wearing surgical masks that said "Freedom of Speech," stood across the street from the Iranian Interests Section on Wisconsin Avenue in Georgetown.

"We are demanding free elections," said Hassan Massali of Potomac, an Iranian who came to this country in 1999.

It could not be determined yesterday how many eligible voters among the estimated 800,000 to 1 million Iranians in the United States went to the 34 polling stations across the country. The polls were open till 9 p.m.

Abolfazi Mehrabadi, deputy director of the interests section, which operates under the Embassy of Pakistan, said that by late afternoon, about 200 people had voted at that site, which was one of four polling stations in the area. The others were in Manassas, Potomac and Timonium, Md.

The 2000 Census counted 17,390 Iranian-born residents in the D.C. area, but activists said they believe there are more.

On the second floor of the interests section, just as Ali Ehteshami of McLean was putting his finger in purple ink, a huge television screen showed Iran's top religious leader, Ayatollah Ali Khamenei, casting his ballot.

Like several other voters yesterday, Ehteshami, a Georgetown University Medical School professor, said he was concerned about escalating tensions between Iran and the United States.

Ehteshami declined to say which candidate he favored, but he said he was voting to show his support for the Iranian government, which "is trying to fix the country."

He added, "We don't want our country to be the same as Iraq. . . . We don't want a U.S. occupation."

Restaurant manager Babak Talebi, 26, said he intended to choose Moin. He said most of his Iranian friends planned to vote because the election is "going to decide if the country is going to go down the reformist path and challenge the conservative hold on the levers of power."

Ali Reza of Reston, 34, a software programmer, drove a friend to the polling station but did not vote himself. "I don't have that much hope of the moving to democracy," he said.

Later, Ali Jazini, director of the interests section, pronounced himself satisfied that "the boycott has failed."

When asked for whom he had voted, Jazini responded with only a laugh.