Votes are being counted in Iran a day after elections that pitted reformist allies of President Hassan Rohani against long-dominant conservatives.
The elections for parliament and a leadership body called the Assembly of Experts are the first since Tehran agreed with major powers to curb its nuclear program.
Interior Ministry officials said on February 27 that the counting of the votes in Tehran and other cities was still not final.
But preliminary results carried out by the semiofficial Fars and Mehr News agencies indicate reformists and independents linked to them were leading so far against hard-liners in several cities.
Earier, the Interior Ministry said 60 percent of eligible voters, about 35 million Iranians, had cast ballots.
Voters are electing a new parliament and a new Assembly of Experts, a key clerical council that chooses and supervises the country's supreme leader.
In the current election, reformists have joined together with moderates and pragmatic conservatives in an electoral list called the "List of Hope."
Conservatives have built their own unity list under the banner "Grand Coalition of Conservatives." The list includes members of the outgoing parliament known for their hostility to Rohani.
A pro-reform voter at a polling station in the northeastern city of Mashhad told RFE/RL's Radio Farda that he'd seen balloting there proceeding smoothly and "it was not too crowded."
Another voter in Tehran told RFE/RL that a polling station in Golhak, in northern Tehran, was packed with voters waiting to cast their ballots.
"Everyone I spoke to say they voted for the two lists of hope [lists of moderate and reformist candidates]."
Other reports from Iranian and international news agencies suggested long lines at polling stations in the capital, Tehran, and Iranian state TV showed large groups of voters in Ahvaz, in the south, and Shiraz, in the southwest.
Iranian opposition figures Mir Hossein Musavi, his wife Zahra Rahnavard, and reformist cleric Mehdi Karrubi -- who have been under house arrest since February 2011 -- have reportedly requested mobile polling stations in order to vote.
The three were put under arrest for repeatedly challenging the Iranian establishment over the disputed reelection of former President Mahmud Ahmadinejad and highlighting human rights abuses.
The opposition website Kalame, close to Musavi, said the former prime minister and his wife, a university professor, managed to cast their ballots at the last minute.
But Karrubi’s son, Taghi Karrubi, wrote on his Facebook page that his father was unable to vote because authorities did not provide him with a mobile box in his home where he’s held under arrest.
He said authorities have not provided any explanation.
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It was not clear which side a high turnout would favor, but Iran's reformists have spent decades grappling with whether to participate in elections in which many of their preferred candidates have been excluded under highly discretionary vetting rules.
'Referendum On Rohani'
But the election is widely seen as a referendum on Rohani's success in clinching a deal in July under which world powers agreed to lift economic sanctions on Iran in exchange for Tehran ending nuclear activities the West said were aimed at acquiring nuclear weapons.
Reformists have sought to capitalize on the deal in their election campaign by emphasizing the benefits ordinary Iranians could reap from increased international economic engagement and foreign investment in Iran.
The deal, which took effect early this year, has freed up tens of billions of dollars of Iranian funds previously frozen in banks outside the country. With renewed access to global financial systems, Iran is now also ramping up its oil exports, the country's main source of revenues.
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However, conservatives and hard-liners who have dominated parliament and other institutions continue to oppose any rapid opening to the West. They mistrust foreign investment and have campaigned for using the expected sanctions-relief windfall to spur growth by investing in domestic production instead.
In the run-up to the February 6 elections, Iran's conservative ruling establishment disqualified large numbers of candidates for both the parliament and the Assembly of Experts in moves that could favor hard-line candidates.
Iran's Guardians Council, which supervises elections, approved only 40 percent of the approximately 12,000 candidates overall who initially registered for the poll. Reformists say the severe vetting excluded many of their most prominent candidates, leaving them with untested hopefuls in many races.
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The outcome of the races for the 290-member parliament will be important for determining the pace of Iran's international trade and economic relations over the next four years of the new parliament's term.
The disqualifications were almost as severe for would-be candidates for the Assembly of Experts, where only 20 percent of applicants were approved.
Reformists say the preelection screening of candidates to the 88-seat assembly has assured that most of those running share the views of the most conservative allies of Supreme Leader Ayatollah Ali Khamenei. That would ensure that an anti-Western stance would be maintained by a successor in the event of his death or incapacitation.
Casting his own ballot early on February 26, Khamenei urged Iranians to flock to the polls while remembering that the country has "enemies."
"Elections should be such that make the enemy disappointed," he told state television after voting. "We must vote with insight and open eyes."
The supreme leader, who holds ultimate decision-making power in Iran's theocracy, does not openly side with any political camp. He supported Rohani's negotiations for a nuclear deal but also shares conservatives' view that the 1979 Islamic Revolution is under constant threat from the West, and particularly the United States.
Khamenei's website quoted him as saying in the run-up to the elections that he was certain that the United States had concocted a plot after the nuclear deal to "infiltrate" Iran.
Correspondents say that many in Iran's conservative establishment fear foreign investment could bring an influx of Western values that would undermine the revolution. They also worry foreign investment could create tough competition for state monopolies, which they frequently control and which dominate the economy.
Reformist leaders have countered by urging voters to view the elections as a chance to build upon Rohani's success in ending sanctions that crippled Iran financially. Independent analysts estimate the country's unemployment rate at 30 percent, with Iranian youth hardest hit.
Nearly 60 percent of Iran's 80 million or so people are under the age of 30.
Almost 55 million Iranians are eligible to cast ballots in the February 26 voting, and there are some 53,000 polling stations nationwide.
The Interior Ministry, which conducts the voting, says election results will be known by late on February 27.