Iran's former president Mohammad Khatami has ended months of speculation by announcing that he will run in June's presidential election, BBC reported.
Mr Khatami was president of Iran from 1997-2005 and was succeeded by Mahmoud Ahmadinejad, a conservative.
"I will seriously take part as a candidate for the election," he told a meeting of a pro-reform group.
In January, a close aide to Mr Ahmadinejad said the incumbent would, as expected, stand for re-election.
Mr Khatami, the most liberal president since the revolution, should have a good chance of unseating Mr Ahmadinejad, arguably the most conservative leader in that time, says the BBC's Jon Leyne, in Tehran.
Mahmoud Ahmadinejad in Tehran, 1 February
Mahmoud Ahmadinejad has been a controversial figure
However, he will face tough opposition from hardliners in the clergy and military, our correspondent adds.
Mr Khatami urged a free election, saying the fate of the Islamic Revolution was at stake.
"Is it possible to remain indifferent toward the revolution's fate and shy away from running in the elections?" he asked at a news conference in Tehran.
"I consider this as a right to run in this stage. This candidacy doesn't deprive others and the path is open. What should be stressed is that the elections must be held freely."
...