Local media reported earlier that Mostafa Ahmadi-Roshan, an Iranian national, was killed by a car bomb attack in Gol Nabi Street near the Ketabi square in northern Tehran on Wednesday morning.
Iran's semi-official Fars news agency reported that an assailant on a motorcycle stuck a bomb on the side of Ahmadi-Roshan's car, killing the man immediately and injuring two other people in the car.
One of the wounded, who was the driver of the car, died in the hospital later Wednesday, according to IRNA.
Earlier media reports identified Ahmadi-Roshan as a university professor, and Fars and local Press TV said he was a "nuclear scientist."
IRNA later quoted an announcement by Tehran's Sharif University as saying that Ahmadi-Roshan was a staff member of Iran's Natanz nuclear enrichment site.
The 32-year-old victim was the deputy chief of Natanz nuclear enrichment site's commercial section, said IRNA.
He graduated from Tehran's distinguished Sharif University in 2003, majoring in chemistry engineering, according to IRNA.
It was not immediately clear whether Ahmadi-Roshan was directly involved in Iran's nuclear program.
Several Iranian nuclear scientists have been assassinated in recent years.
Iran's First Vice-President Mohammad-Reza Rahimi said Wednesday that Israeli agents were the perpetrators of Ahmadi-Roshan's assassination, IRNA reported.
The enemies should know that they will not be able to stop Iran's scientific progress by such terrorist acts, Rahimi was quoted as saying.
According to Fars, Iran's Majlis (parliament) National Security and Foreign Policy Commission will hold a meeting on Wednesday to study the incident.