The conservatives remain divided, but attention has lately focused on hardline cleric Ebrahim Raisi, 56, who runs the powerful Imam Reza charitable foundation. But many hard-liners in Iran seek a tough-talking candidate to rally around who can stand up to U.S. President Donald Trump.
The most high-profile candidate to register thus far is former hard-line President Mahmoud Ahmadinejad.
Rouhani, a moderate cleric, also said that if he is elected to a second term, he will continue a practice of being transparent with the Iranian people.
Iranian President Hassan Rouhani speaks at a news conference near the United Nations General Assembly in the Manhattan borough of NY, U.S., September 22, 2016. Under Iran's Constitution, a president can not serve for three terms in a row.
Following Supreme Leader Ayatollah Ali Khamenei's recommendation in December that Ahmadinejad stay out of the race, moderate President Hassan Rouhani was seen to have a wide-open path to reelection.
Almost 50.5 million Iranians were eligible to vote in the 11th presidential election, and the voter turnout in the polls stood at 72.7 percent.
According to Shakdam, Ahmadinejad's decision to run was not an act of defiance but simply a choice based on his willingness to offer a "different kind of a flavor in politics" and ensure that the voices of his faction are heard, especially in the context of the current tension between the US, Iran and Russian Federation, and around the Middle East in general.
Some 863 hopefuls have signed up since registration opened on Tuesday, said Ali-Asghar Ahmadi, head of election headquarters at the Interior Ministry.
Both Rouhani and Raisi on Friday avoided raising controversial issues, acquiescing to a longstanding demand by Khamenei who had urged a non-polarized election.
On April 28, candidates start campaigning until 24 hours before May 19, the voting date for the 12th presidential and 5th city and council elections.
The clerical body will announce a final list of vetted candidates on 27 April.