An Iranian nuclear scientist has died in a bomb blast in Tehran.
Iranian news agencies said the scientist died when a magnetic bomb attached to a car by a duo on a motorbike exploded. Two other people were injured in the blast.
An Iranian official immediately blamed "the Zionist regime" for the explosion, similar to attacks on scientists just over a year ago.
The explosion occurred outside the east Tehran campus of Allameh Tabatai University, at its social sciences faculty.
Fars news agency identified the victim as 32-year-old Mostafa Ahmadi Roshan, who was a graduate of an oil industry university. He had supervised a department at Iran's Natanz uranium enrichment facility.
"The bomb was a magnetic one and the same as the ones previously used for the assassination of the scientists, and the work of the Zionists (Israelis)," Fars quoted Deputy Tehran Governor Safarali Baratloo as saying.
Mostafa Ahmadi Roshan is not the first Iranian scientist to be killed in a bomb blast in Tehran.
Two daylight bomb attacks on the same day in Tehran in November 2010 killed one nuclear scientist and wounded another.
Iran then blamed Israeli, British and US intelligence for the attacks, which it said were aimed at assassinating key people working on Iran's nuclear programme.
Iran denies Western suspicions that its nuclear programme has military goals, saying it is for purely peaceful purposes.
The White House has denied any US role in the attack.
"The United States had absolutely nothing to do with this," White House spokesman Tommy Vietor said.
"We strongly condemn all acts of violence, including acts of violence like what is being reported today."
