The two main contenders to become Iranian president, hardline judiciary chief Ebrahim Raisi and former parliament speaker Ali Larijani, registered on Saturday to run in next month's election.

US President Donald Trump is not fit for his job, the speaker of Iran's parliament said on Wednesday, in Tehran's most personal criticism since Trump's decision to withdraw from a 2015 nuclear pact between Tehran and six world powers.

Moderate conservative Ali Larijani retained the speakership of Iran's parliament despite major gains for reformists in February elections, benefiting from credit gained by his support for last year's nuclear deal.