Iran's powerful former president Akbar Hashemi Rafsanjani has entered the race for the June presidential election.
Simultaneously, President Mahmoud Ahmadinejad's close confidant Esfandiar Rahim Mashaei also signed up in the last minutes before Saturday's registration deadline.
State TV showed both men at the Interior Ministry registering their names. A smiling Mr Ahmadinejad accompanied Mr Mashaei and raised the man's hand in a gesture of support.
The registration of the two hopefuls puts forward a tough challenge to conservative candidates loyal to Supreme Leader Ayatollah Ali Khamenei and will likely intensify competition between rival groups at the June 14 vote.
Mr Rafsanjani is now the prime hopeful for reformists, who were widely crushed and left leaderless after massive street protests following Mr Ahmadinejad's disputed 2009 election victory.