Iran opened a five-day registration period on Thursday for hopefuls wanting to run in the June 28 presidential election to replace the late Ebrahim Raisi, who was killed in a helicopter crash earlier this month with seven others.

The election comes as Iran grapples with the aftermath of the May 19 crash, as well as heightened tensions with Israel and the United States.

The period would see those between the ages of 40 to 75 with at least a master's degree register as potential candidates.

All candidates ultimately must be approved by Iran's 12-member Guardian Council, a panel of clerics and jurists ultimately overseen by Supreme Leader Ayatollah Ali Khamenei.

That panel has never accepted a woman nor anyone calling for radical change within the country's governance.

It is unlear who will run. The country’s acting president, Mohammad Mokhber, a previously behind-the-scenes bureaucrat, could be a front-runner, because he's already been seen meeting with Khamenei.

Also discussed as possible aspirants are former hard-line President Mohammad Ahmadinejad and former reformist President Mohammad Khatami.

The five-day registration period will close on Tuesday.

The Guardian Council is expected to issue its final list of candidates within 10 days afterwards.

That will allow for a shortened two-week campaign before the vote in late June. (AP)