The Iranian intelligence agents managed to penetrate the Israeli Secret Intelligence Service Mossad to study the internal security system and reveal the agents activated by the Israeli special services, Iranian Minister of National Security Heydar Moslehi said.

Iran's intelligence services said Monday they have arrested suspects in the assassination a year ago of a nuclear physicist in a months-long covert operation that also led them to penetrate Israel's Mossad spy agency, the Associated Press reported.

Iran blames the Mossad for the slaying of Tehran University physics professor Masoud Ali Mohammadi, who was killed by a bomb-rigged motorcycle that exploded outside his house as he was leaving for work in January 2010. Possible explanations for why he was targeted have never been clear, particularly as he had no known link to Iran's nuclear work, but Iranian state media have presented it as an attempt to slow the atomic program.

Earlier announcement said Iranian agents arrested a network of spies linked to the slaying, opening up revelations about further Israeli plots against the country, including a campaign to assassinate nuclear scientists.