An Iranian nuclear scientist has been killed and two people injured when a magnetic bomb attached to a car by a duo on a motorbike exploded outside a Tehran university, Iranian news agencies said.

An Iranian official said Israel was behind the attack, pointing to similarities with previous killings of other nuclear scientists.

A policeman walks past the car belonging to Iranian nuclear scientist Mostafa Ahmadi Roshan outside a university in northern Tehran. Credit:Reuters

The person killed was identified by several media as Mostafa Ahmadi Roshan, a scientist who worked on separating gases at the Natanz uranium enrichment facility, according to the website of a different university from which he graduated around a decade ago.

"This morning a motorbiker attached a bomb to a Peugeot 405, which exploded," the governor of Tehran province, Safar Ali Bratloo, was quoted as saying by the ILNA news agency today.