Incomplete returns in the race for Iran's president showed five candidates locked in a tightly packed cluster, with the only certainty being that the final outcome would be determined by a two-man runoff set for June 24.

With about 60 percent of ballots counted, officials of Iraq's appointed Guardian Council announced preliminary rankings that showed two time president Ali Akbar Hashemi Rafsanjani with a narrow lead with 21.7 percent of the vote, and moderate cleric Mehdi Karrubi six-tenths of a percentage point behind.

The next group of candidates was led by Tehran Mayor Mahmud Ahmadinejad, a dark horse running with 16.1 percent nationwide, but stronger at his base: With half the ballots counted in the capital Ahmadinejad was winning Tehran outright.

Mostafa Moin, a former culture minister who embodied the hopes of Iran's reformist movement, was running fourth with 14.7 percent, slightly ahead of former national police chief Mohammad Qualibaf.

With seven candidates splintering Friday's vote, the presidential contest was easily the tightest since Iran established religious rule following the 1979 overthrow of an American-backed monarch. No presidential ballot has gone to a second round, required when no candidate tops 50 percent.

Voter turnout nationwide was 57 percent, according to an interior ministry official, slightly higher than the ministry predicted. Polls remained open four hours beyond their scheduled closing, to 11 p.m., as state television urged a turnout that would lend credibility to a candidate list orchestrated by the country's unelected clergy.

Rafsanjani, who twice served as president in the 1980s, had led in pre-election polls, and according to early returns and his campaign's own exit poll, appeared poised for a substantial, if not decisive win.

Moin, a low key former minister of higher education, was running close behind. But Ahmadinejad was already doing surprisingly well, reflecting a late surge in support from voters impressed by a markedly austere campaign that played up his working-class background and religious roots.

Karrubi, a former parliament speaker, also showed unexpected strength, after ballot counters first cautioned that the early returns were drawn from his geographic base and might not hold up.

Also in the mix was former police chief Qualibaf, one of several conservative candidates who campaigned as reformists, despite backgrounds in hard-line institutions that opposed social and political freedoms championed by outgoing President Mohammad Khatami.

Khatami, forbidden from serving a third consecutive term, eight years ago was swept into office on the hopes of the youthful generation that is reshaping Iranian domestic politics, an under-30 majority eager to remove the U.S. sanctions that many here equate with sluggish economic development.

All candidates said they favored restoring diplomatic ties with the United States, severed after Islamic radicals took U.S. diplomats hostage for more than a year after the revolution.

Rafsanjani, a millionaire and moderate cleric, has emphasized his negotiating credentials as a "pragmatic conservative." His business interests run deep in Iran's state-dominated economy, and he is often called the country's richest man.

"He's well-off, so there's little risk of him getting himself involved in corruption," said Tahere Dasht, 19, explaining her vote.

Reformists were upbeat throughout the day, citing strong support for Moin in outlying provinces heavily populated by minorities, including the ethnic Kurdish northwest and the desert reaches of Sistan and Baluchistan.

Turnout was low for a presidential election in Iran, but not a record. In advance of Friday's ballot, hard-line clerics had pointed out that such figures were comparable to turnout in American elections and should not be interpreted as a test of the system's legitimacy, as dissidents maintain. Ayatollah Ali Khamenei declared that a vote cast for any candidate Friday was a vote "for the Islamic system." Khamenei holds the title of Iran's Supreme Leader, and along with three bodies dominated by unelected clerics, wields authority beyond any elected official.

Some Iranians said they decided to vote after hearing President Bush discount the credibility of Friday's ballot. The White House on Thursday issued a statement saying Iran's electoral process "ignores the basic requirements of democracy."

The candidate slate was culled by the country's Guardian Council, a much-criticized panel dominated by clerics who disqualified more than 1,000 presidential candidates, including all female hopefuls.

"Iranians turned out today because we want to say to the world we don't want anybody to decide for us," Goli Mitrazad said after casting her ballot at a landmark Tehran mosque.

A larger-than-expected turnout stood to boost reformists. After years of seeing Khatami thwarted, reformists have struggled to sustain the enthusiasm of the large majority of Iranian voters who twice voted him into office. In the weeks before Friday's ballot, it was difficult to find residents of the capital who said they planned to vote. After seeing their hopes for dramatic change wither under Khatami, many indicated they would avoid ballot boxes as a protest, and as a way of restoring wounded pride.

At a west Tehran polling station, an activist trying to boost turnout implored three young women displaying their hair and figures to an extent that would have landed them in jail even four years ago. They would vote for Moin if they could bring themselves to care enough, they said, but they were only waiting for a friend.

"You can make a 10 percent difference at least," Javad Mostoufi said. "If you don't vote, it's going to be Hashemi again," he said, referring to Rafsanjani by the middle name the candidate has used on bumper stickers. "It's stupid not to vote."

Special correspondent Mehrdad Mirdamadi contributed to this report.

Iranian women vote in the Huseiniya Ershad mosque in Tehran. All female candidates were excluded from the ballot.