Tehran, May 20 (IANS): Counting is underway on Saturday in Iran's Presidential election, with the official turnout said to be at about 70 per cent, poll officials said.

Millions of Iranians flocked to polling stations on Friday to vote in the election that pits incumbent President Hassan Rouhani, who is seeking a second term, against a strong conservative opposition.

Rouhani's main challenger is Ebrahim Raisi, a hardline cleric and former prosecutor who is close to Supreme Leader Ayatollah Ali Khamenei.

According to the Interior Ministry, over 40 million votes were cast on Friday and voting time was extended by five hours due to "requests" and the "enthusiastic participation of people", reports the BBC.

If no-one wins more than 50 per cent of votes cast, a run-off will be held next week.

Every incumbent President has been re-elected in Iran since 1985, when Ayatollah Ali Khamenei himself won a second term.

He cast his ballot just minutes after polls opened at 8 a.m.

Rouhani voted about an hour later.

More than 54 million people were eligible to vote in the presidential election.

Six candidates were approved by the Guardian Council, an influential clerical body controlled by conservatives, but two of them dropped out earlier this week, the BBC reported.

The first was Tehran's hard-line mayor, Mohammed Baqer Qalibaf, who pledged his support for Raisi on Monday.

He was followed on Tuesday by Vice-President Eshaq Jahangiri, a reformist, who pulled out to smooth the path for Rouhani.

The two other candidates still in the race are Mostafa Hashemitaba, a reformist, and Mostafa Mirsalim, an ultra-conservative figure.