A former head of Iran's Revolutionary Guards says he will run for president, posing a conservative challenge to incumbent Mahmoud Ahmadinejad.

Mohsen Rezai has criticized Mr. Ahmadinejad's handling of the economy, which suffers from inflation and depressed revenues due to the fall in oil prices.

Rezai is also critical of Iran's two main political factions, the moderate Reformists and the conservative Principlists, and has floated the idea of a coalition government uniting the two.  

Candidates must register for the poll in early May.  Elections are set for June 12.

Some information for this report was provided by AP.