Moderate cleric Hassan Rowhani has taken an early lead in Iran's presidential vote counting, in what could be the makings of a surprise victory over the nation's ruling hardliners.
Rowhani -- the favorite of reformists and a former chief nuclear negotiator -- had 51 percent of the 23 million or so votes counted by Saturday afternoon. The next closest candidate, Tehran Mayor Mohammad Bagher Qalibaf, trailed far behind with less than 17 percent of the votes.
The final results are expected to be announced by late Saturday. About 50 million Iranians were eligible to vote Friday, with turnout estimated at above 70 percent.
A candidate must get more than 50 percent of the vote to win the election and avoid a runoff next Friday.
The winner will succeed President Mahmoud Ahmadinejad, who is constitutionally barred from a third consecutive term.
This is Iran's first presidential vote since Mr. Ahmadinejad's disputed re-election in 2009 spawned widespread protests and a bloody crackdown by the government.
Analysts say the high interest in the carefully orchestrated campaign may be due to the candidacy of moderate cleric Rowhani.
Officials extended voting by several hours Friday to accommodate what they described as a large turnout in the presidential election.
Whoever wins will face an economy struggling with high unemployment and inflation and crippled by international sanctions over Iran's disputed nuclear program.
Most of the six candidates are considered hardliners who are loyal to the country's supreme leader, Ayatollah Ali Khamenei.
While some candidates favor improved ties with the international community, the election outcome is unlikely to alter Iran's relationship with the outside world, as major policy decisions rest with the supreme leader.