Iran has called the killing of a prominent nuclear scientist a “terrorist act,” as key officials suggested the U.S. and Israel are behind the attack. Mostafa Ahmadi Roshan died after an unidentified motorcyclist attached a magnetic explosive to his car. Roshan was a professor at Tehran’s technical university; he was also a department supervisor at Natanz, a uranium enrichment facility where Iran is suspected to be working toward nuclear weapons capability. Several scientists have been attacked in similar fashion over the past two years, according to the semiofficial Fars news agency. A survivor of one such attack, Fereydoon Abbasi is now the head Iran’s Atomic Energy Organization. In a statement quoted by Reuters, the organization said: “America and Israel’s heinous act will not change the course of the Iranian nation.” On Jan. 23, European leaders are meeting to discuss a possible oil embargo intended to dissuade Iran from pursuing its uranium enrichment program. Iran says its nuclear efforts are peaceful.