Iranian radio says there's been another explosion in Teheran, hours after two people died in what may have been a bomb attack at the Revolutionary Prosecutor's Court.

The radio said a public building was damaged in the north of Teheran but that no-one was hurt.

It also reported that an un-named armed group had tried to attack a third building -- the headquarters of the Revolutionary Guard -- but ran away, leaving behind explosives.

The Iraq-based opposition group, the Mujahedin Khalq, claimed it was behind the original attack -- and the authorities have urged the public to attend the funerals of those who died as a sign of protest.

Correspondents say there may be a connection between the explosions and the anniversary on Thursday of the death of the founder of the Islamic Revolution, Ayatollah Khomeini.