The race for Iran's highest elected office was revitalised on Saturday when former president Akbar Hashemi Rafsanjani and top nuclear negotiator Saeed Jalili officially registered for the June 14 election.
Rafsanjani, who was president between 1989 and 1997, registered at the interior ministry in the closing minutes of the five-day registration process for the presidential vote which wrapped up on Saturday.
The final line-up of candidates will not be known until later this month when the Guardians Council releases the approved list of names after the vetting process.
"I came to serve. It is the right of the people to choose me or not," Rafsanjani was quoted by Iranian media as telling reporters.
He is seeking to succeed Mahmoud Ahmadinejad whose two-term presidency has left the Islamic republic isolated internationally, while the ailing economy struggles to cope with international sanctions over Tehran's nuclear ambitions.
Rafsanjani, who will be 79 in August, had polarised Iran's complex political spectrum in recent weeks by announcing that he was considering standing again.
He has been isolated by ultra-conservatives since Ahmadinejad's disputed re-election in 2009 sparked massive street protests, leading to a heavy-handed regime crackdown and the arrest of hundreds of journalists, activists and reformist supporters.
Rafsanjani at the time called for the release of those rounded up during the demonstrations.
Also on Saturday, Saeed Jalili, Iran's top nuclear negotiator and close figure to all-powerful supreme leader Ayatollah Ali Khamenei, unexpectedly showed up at the ministry and registered his candidacy.
A veteran of the 1980s war with Iraq in which he lost his lower right leg, Jalili, 47, did not speak to reporters, an AFP correspondent said.
Jalili heads the team in negotiations with world powers over Tehran's controversial atomic activities which the West fears are aimed at developing a military capacity, a claim denied by Iran.
In Istanbul on May 15 Jalili is scheduled to meet the European Union's top diplomat Catherine Ashton, who represents the so-called P5+1 group of Britain, China, France, Russia and the United States plus Germany in nuclear talks with Iran.
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Their last meeting in April in the Kazakh city of Almaty left the two sides "far apart", according to Ashton.
All decisions on key state affairs, including the nuclear issue, rest with Khamenei.
Before taking over as the secretary of Iran's Supreme National Security Council, Jalili was a deputy foreign minister and also held a position in Khamenei's office.
Unlike Rafsanjani who has been critical of Ahmadinejad's economic and foreign policy, Jalili has not been vocal on domestic issues.
Ahmadinejad is constitutionally barred from seeking a third consecutive term. But on Saturday he endorsed his controversial aide and ex-chief of staff Esfandiar Rahim Mashaei, walking him to the interior ministry.
"I am under an obligation to follow in the footsteps of the Ahmadinejad government," Mashaei, the bane of the conservatives for his liberal views, told reporters.
Mashaei's appointment as first vice president was overturned by Khamenei in 2009, sparking a rift between the president and conservatives loyal to the supreme leader.
It is not clear whether Mashaei will pass the Guardians Council test. The unelected body is controlled by religious conservatives appointed by Khamenei.
The council is tasked with vetting the candidates to ensure they adhere to constitutional conditions of being faithful to the principles of the Islamic republic and its official religion, before announcing the final list of hopefuls no later than May 23.
The decisions by Rafsanjani and Jalili overshadowed earlier registrations of a handful of conservative hopefuls, including veteran diplomat Ali Akbar Velayati, Tehran mayor Mohammad Baqer Qalibaf, former Revolutionary Guards commander Mohsen Rezaei, ex-foreign minister Manouchehr Mottaki and former health minister Kamran Bagheri Lankarani.
No high-profile candidates from the reformist camp, suppressed after the 2009 events, have registered, but local reports say reformist former president Mohammad Khatami has unofficially endorsed Rafsanjani.
According to the interior ministry, some 686 candidates have registered, including 30 women. Approved candidates will have three weeks to campaign before polling day on June 14.