Outgoing Iranian President Mahmud Ahmadinejad has vowed to reverse a decision to disqualify his top aide from the June 14 presidential election.
On May 21, Iran's Guardians Council of clerics and jurists denied Esfandiar Rahim Mashaei a place on the ballot.
The council approved only eight of nearly 700 potential presidential candidates, mostly hard-liners loyal to Supreme Leader Ayatollah Ali Khamenei.
Ahmadinejad said on May 23 that he will take up Mashaei's disqualification with Khamenei, calling it an act of "oppression."
He described Mashaei as "a righteous person" and said he was "hopeful the problem will be solved."
Mashaei is viewed by some figures from Iran's conservative establishment as too close to Ahmadinejad, who has had tense relations with Khamenei.
Ahmadinejad, who cannot seek a third consecutive term under Iranian law, is also seen as attempting to maintain power through Mashaei.
Leading candidate Akbar Hashemi Rafsanjani, a former Iranian president seen as a relative moderate, was also barred from the election.
Rafsanjani, who will turn 79 in August, currently chairs the Expediency Council, Iran's highest political arbitration body.
The Guardians Council, without naming Rafsanjani, said frailty and old age had been factors in the eliminations.
The U.S. State Department has criticized the move, accusing the Guardians Council of handpicking candidates "based solely on whom the regime believes will represent its interests, rather than those of the Iranian people."
Chief nuclear negotiator Said Jalili and Khamenei's foreign policy adviser, Ali Akbar Velayati, are among the approved candidates.
Jalili, 47, heads Iran's Supreme National Security Council. He previously served as deputy foreign minister for European and American affairs.
Velayati, a trained pediatrician, served as foreign minister for more than sixteen years.
Another top candidate is Mohammad Baqer Qalibaf, the mayor of Tehran and a staunch Khamenei loyalist. Qalibaf is a former military and police commander and holds a Ph.D. in geopolitics. He has admitted to personally taking part in a brutal crackdown on student protests in 1999.
Mohsen Rezai, a former head of the Revolutionary Guards, will also stand in the election. He is the secretary of the Expediency Council and ran as a conservative candidate in the 2009 presidential elections, coming in third. Rezai teaches economics at the Imam Hossein University, which he co-founded.
Candidate Gholam Ali Haddad-Adel was the Iranian parliament's speaker between 2004 and 2008. A philosopher and physicist by education, he served in many governmental posts, including deputy minister of education and head of the Iranian Academy of Persian Language and Literature.
Several moderate candidates were also allowed to run for president.
These include former nuclear negotiator Hassan Rohani, a figure close to Rafsanjani, and Mohammad Gharazi, a former minister.
Rohani, 64, heads the Expediency Council's Political, Defense, and Security Committee and is also a member of the Supreme National Security Council. He has pledged to improve civil rights, restore the economy, and mend relations with the West if elected.
Gharazi served as telecommunications minister under Rafsanjani, who was president from 1989 to 1997, and under opposition leader Mir Hossein Musavi, who served as prime minister between 1981 and 1989.
Mohammad Reza Aref is considered the only reformist on the list of approved candidates.
Aref, 61, studied electrical and communication engineering at Stanford University in the United States.
A former minister of communications and information technology, he also served as Iran's first vice president under opposition leader Mohammad Khatami.
With reporting by Reuters, AP, and AFP