Former Iranian president Mohammad Khatami says he is backing moderate Hassan Rowhani in Friday's presidential election.
Khatami's endorsement Tuesday follows the withdrawal of pro-reform candidate Mohammad Reza Aref, who says he dropped out after receiving a letter from Khatami telling him it would not be wise to remain in the race.
Reformists had been calling on supporters to vote for Rowhani, the only cleric in the race.
Aref is the second candidate to drop out this week. Conservative Gholam Ali Haddad Adel withdrew Monday, leaving six men vying to replace President Mahmoud Ahmadinejad.
Iran's Guardian Council of clerics and jurists approved the list, which is dominated by ultraconservative loyalists of Supreme Leader Ayatollah Ali Khamenei. Mr. Ahmadinejad cannot run for a third term under Iran's constitution.