Around 60 percent of voters cast ballots in Iran’s elections after polling stations were kept open to allow millions of Iranians to participate, Tehran’s interior ministry said on Saturday.

Around 60 percent of voters cast ballots in Iran's elections after polling stations were kept open to allow millions of Iranians to participate, Tehran's interior ministry said on Saturday.

At least 33 million out of 55 million eligible voters took part in polls for the parliament and the Assembly of Experts, interior ministry Hossein-Ali Amiri told state television.

"The numbers will increase" as not all ballots have been counted, Amiri added.

A second round will be organized in a number of cities for seats where no candidate received more than 25 percent of votes, he said, without providing further details.

Definitive results must be confirmed by the Guardian Council -- charged with monitoring the vote -- and are not expected for several days.

The first results are expected to come from the provinces, but the vote tally in the capital, which has a population of 12 million and was electing 30 lawmakers, will take around three days.

Supreme Leader of the Islamic Revolution in Iran , Imam Sayyed Ali Khamenei was among the first to vote and he urged the country's 55-million-strong electorate to follow suit, as "it's both a duty and a right".

Currently, the Iranian Parliament has 290 representatives fourteen of whom represent non-Muslim religious minorities. Women constitute about eight percent of the Parliament members.

A total of 4,844 candidates, including about 500 women, who have been qualified from amongst 12,000 registered candidates by the Guardian Council, are taking part in the competition to occupy parliamentary seats.

At least 21 people will vie for each seat in the legislature.

The elected candidates will serve from May 3, 2016 for a four-year term.