Iranian President Hassan Rouhani, a pragmatist who championed the country's nuclear deal with world powers, registered on Friday to run for a second four-year term in the May presidential election, state TV reported.
Rouhani won election by a landslide in 2013 on a platform of ending the Islamic Republic's diplomatic isolation and creating a freer society.
The five-day registration period for the May 19 election started on Tuesday and will be followed by a process of vetting of the hopefuls by a hardline watchdog body, The Guardian Council.
Over 860 people have signed up so far for the vote. Several former ministers and hardliner former president Mahmoud Ahmadinejad are among those who have registered.
Despite months of talks, hardliners have been unable to unite behind a single candidate and Supreme leader Ayatollah Ali Khamenei appears to have not yet intervened to make them do so.
Within Iran's complex mix of clerical rulers and elected officials, Khamenei has the final say on all state matters.
Influential cleric Ebrahim Raisi, the custodian of a powerful organization in charge of Iran’s holiest shrine, appears to be the leading hardline candidate.
An ally of Khamenei, Raisi has yet to register for the vote, however. Prominent conservatives, including parliament speaker Ali Larijani, have thrown their support behind Rouhani.