With Iranian nuclear talks set to begin in early December, Iran's nuclear program was set back with computer viruses and a successful assassination of an Iranian scientist.
In separate attacks in Tehran, two Iranian nuclear scientists were targeted in explosions by men who appear to have escaped on motorcycles. One of the scientists was assassinated, and the other was seriously injured.
The incidents were blamed on Israel's Mossad and on America's CIA operatives by local Iranian media sources. Both countries have denied involvement in the attacks.
"Dr. Shahriari was killed and his wife and driver were injured. Dr. Abbasi and his wife have been injured," Tehran police chief Hossein Sajedi-nia was quoted by an AFP report.
"The head of Iran's atomic energy organisation, Ali Akbar Salehi, confirmed Dr Shahriyari was involved in a 'major project,'" The Telegraph reported.
Iran's nuclear ambitions have been the focus of fierce scrutiny by Western nations that believe the Iranian regime is seeking nuclear weapons. Iran denies that their interest in nuclear development is for weaponization.
The Iranian program has also been hit with sophisticated computer viruses - in what appears to be a coordinated effort to sabotage the Islamic nation's progress.
Talks between US, Germany, UK, France, Russia and Iran have been scheduled for December 5 in Geneva.