Two bombs were handed over to the Party for Free Life of Kurdistan (PJAK) in the Iraqi city of Arbil by the Americans, the Resalat daily reported on Monday.
The first bomb killed Ahmadi Roshan, but the second one was discovered by intelligence and security personnel around Resalat Square in the capital Tehran, the report said.
On January 11, Ahmadi Roshan was killed after a motorcyclist attached a magnetic bomb to his car in Tehran. Ahmadi Roshan was a chemical engineer and served as the deputy director of marketing at Iran's Natanz nuclear facility. The slain scientist was not the first Iranian nuclear expert targeted by a terrorist attack.
In November 2010, Majid Shahriari, was killed in a terrorist attack and Fereydoun Abbasi, the current head of the Atomic Energy Organization of Iran, sustained injuries in another attack.
Professor Masoud Ali-Mohammadi, a scholar at Tehran University, was also assassinated by a booby-trapped cycle of violence in the Iranian capital in January 2010.
The US and its allies have resorted to various terrorist tactics to stop Iran's peaceful nuclear program, which is under full observation of the inspectors of the ineffective International Atomic Energy Agency.