Hassan Rouhani ahead in Iran poll

Moderate cleric Hassan Rouhani has taken a commanding lead in Iran's presidential election based on the latest results, with about 14 percent of the total votes counted.

According to the Reuters news agency, Rouhani, a former nuclear negotiator, leads with 2,720,144 votes, 52.3 percent of counted votes. 

Rouhani is followed by Tehran mayor Mohammad Baqer Qalibaf with 903,389, 17.3 percent of the votes.

In third place was Iran's chief nuclear negotiator, Saeed Jalili, with 679,524 votes, followed closely by Mohsen Rezaei, a former head of the elite Revolutionary Guard, with 536,725 votes. 

Trailing the field were former Foreign Minister Ali Akbar Velayati with 305,529 votes, and little-known former minister Mohammad Gharazi with 65,934 votes.

Earlier, Interior Minister Mostafa Mohammad Najjar told state television on Saturday that his electoral staff would not "compromise accuracy for speed". 

Iran's state-owned news network Press TV said that voter turnout in the presidential election has been around 80 percent.

Polling stations stayed open for up to five hours later than planned as millions of Iranians turned out to cast their votes.

An announcement of initial results by the Interior Ministry, scheduled for around 1:30am local time, was then postponed by several hours.

Before the polls closed, all six of the presidential candidates issued a joint appeal for calm.

"We ask people not to pay attention to rumours of victory parades being organised and to avoid gathering before the official results" are announced by the interior ministry, their statement said.

Polling hours had been extended a further hour in the capital, Tehran, in the face of what officials reported was a turnout almost as large, or bigger, than that for the controversial re-election of Mahmoud Ahmadinejad four years ago.

In 2009, turnout reached 85 percent nationwide. More than 50.5 million Iranians were eligible to vote for the man to succeed Ahmadinejad, who is constitutionally barred from standing for a third term. 

The full results are expected on Saturday, but if no candidate secures more than half of the votes for an outright victory, the top two will square off in a second-round run-off on June 21.

The campaign has been dominated by Iran's controversial nuclear programme and an economy devastated by harsh EU and US sanctions imposed in an attempt to rein it in.

Inflation is raging at more than 30 percent, the rial has lost nearly 70 percent of its value and unemployment is rising.

Western governments and Israel accuse Iran of seeking to develop atomic weapons under cover of its civil nuclear programme, a charge it denies.