Early results from Iran's presidential election put the reformist-backed candidate, Hassan Rouhani, in the lead, BBC News reported.

With 2.9m ballots counted, the cleric had 1.46m votes, or 49.87%, well ahead of Tehran mayor Mohammad Baqer Qalibaf, with 488,000 votes, or 16.65%.

If no candidate wins more than 50%, a run-off will be held next week.

Electoral officials said turnout was high among the 50 million Iranians who were eligible to vote on Friday, June 14 for a successor to Mahmoud Ahmadinejad.

The interior ministry began releasing preliminary figures early on Saturday after a delay of several hours.

Voting was extended until 23:00 local time (18:30 GMT) to allow more people to cast their ballots. Press TV said that turnout was 80%.

It is unclear when the final results will be known, but by 08:00 (03:30 GMT), with about 7.5% of votes counted, Rouhani had more than twice as many as his nearest rival.

Although all six candidates are seen as conservatives, analysts say Rouhani - a 64-year-old cleric often described as "moderate" who has held several parliamentary posts and served as chief nuclear negotiator - has been reaching out to reformists in recent days.