Iranian media say a bomb blast in Tehran has killed a university professor who also worked as a scientist on Iran's nuclear program.

The Fars news agency said someone on a motorcycle planted the bomb under the car of Mostafa Ahmadi Roshan, and Iranian officials have blamed Israel for the attack.

The report said two other people were wounded by the Wednesday blast in the northern part of the capital.

Fars said Roshan supervised a department at the Natanz nuclear facility. Iran has been enriching uranium to relatively low levels at the above-ground site.

Iranian officials confirmed Tuesday that a new underground complex has started refining uranium, and diplomats with ties to the U.N. nuclear agency say the work is being done at a much higher lever of purity.

Attackers have killed or wounded several Iranian nuclear scientists in recent years, including blasts in late 2010 that state media also attributed to bombs placed on cars by motorcyclists.

Iranian officials blamed the U.S. Central Intelligence Agency and Israel's Mossad intelligence agency for those attacks.

The U.N. Security Council has imposed four sets of sanctions on Iran for refusing to stop enrichment work, which has civilian and military uses. Western powers accuse Iran of trying to develop a nuclear weapon. Tehran says its nuclear ambitions are peaceful.