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Fars News Agency, Associated Press
This undated photo released by Iranian Fars News Agency, claims to show Mostafa Ahmadi Roshan, who they say was killed in a bomb blast in Tehran, Iran, on Wednesday, Jan. 11, 2012. Two assailants on a motorcycle attached a magnetic bomb to the car of an Iranian university professor working at a key nuclear facility, killing him and his driver Wednesday, reports said. The slayings suggest a widening covert effort to set back Iran's atomic program. The blast killed Mostafa Ahmadi Roshan, a chemistry expert and a director of the Natanz uranium enrichment facility in central Iran, state TV reported.

TEHRAN, Iran — A semiofficial Iranian news agency is quoting a senior military officer as saying that Tehran is preparing to "punish" whoever orchestrated the assassination of a nuclear scientist.

Iran has blamed the U.S., Israel, and to a lesser extent Britain for the Wednesday killing of Mostafa Ahmadi Roshan.

Spokesman for Iran's Joint Armed Forces Staff Gen. Masoud Jazayeri was quoted by Isna agency on Saturday as saying that Iran was "reviewing the punishment" of "behind-the-scene elements" involved in Roshan's death.

The U.S. has denied any role in the slaying. Britain's Foreign Office condemned the killing of civilians. Israeli officials, in contrast, have hinted at covert campaigns against Iran without directly admitting involvement.