The results of the elections will probably not be known for days due to the extraordinarily high number of candidates.

Nationally, about 330,000 candidates, including 5,000 women, ran for almost 200,000 seats.

Jim Muir: "This is the most open election for many years"

Turnout was reported to be massive in many areas with some cities extending voting hours and polling stations running out of ballot papers.

It was the first chance since the Islamic revolution for Iranians to choose the powerful councils that run their towns and cities.

Most outcomes are expected by the end of the weekend, but the results for some cities could take up to a week.

Correspondents say Tehran - where there was a large turnout, particularly among young people - could be one of the last to declare. Some 4,200 candidates competed for just 15 seats in the capital.

Battle ground

The election has been seen as a key battle ground between supporters of the reformist President Mohammed Khatami and his conservative opponents.

President Khatami: Elections "symbol of political reform"

Casting his vote in a northern Tehran mosque, President Khatami said the election was the centrepiece of his efforts to extend democracy throughout the country.

"The elections are the greatest symbol of participation and political reform," President Khatami said.

"They are to ensure people know their rights in shaping their destiny. It is also a giant step towards decentralisation, which is a goal of the new government," he said.

But parliamentary speaker Ali Akbar Nateq-Nuri said a heavy turnout would favour his hardline Islamists, who oppose Mr Khatami's reformist agenda.

"The people's participation in different arenas will encourage the friends of the Islamic revolution and disappoint its enemies," Mr Nateq-Nuri said.

Jim Muir: "The competition is fierce"

BBC Tehran Correspondent Jim Muir says Mr Khatami's message appeals to the country's majority - the young - and the elections set an important precedent for next year's general election when the reformists will be trying to win control of parliament from the conservatives.

Although local elections were always envisaged under the Islamic constitution, it is President Khatami who provided the impetus in line with his philosophy of giving power to the people.

All Iranians over the age of 15 - about 40 million of the country's 60 million population - were eligible to vote.

More moderates allowed to stand

Less than 24 hours before the polls were due to open, several previously barred, moderate candidates were allowed to participate.

According to the Iranian news agency, President Khatami overruled a disqualification order issued against 11 Tehran candidates by a conservative-controlled supervisory council.

The head of the council had threatened to cancel the polls in Tehran unless the Interior Ministry agreed to bar the candidates.