Iran's top nuclear scientist was killed on Friday in an alleged assassination that the country's foreign minister linked to Israel. Mohsen Fakhrizadeh, considered one of the masterminds of Iran's controversial nuclear program, died after his car was apparently ambushed in a district east of Tehran. Photos from the scene showed the shattered windshield of a car, and blood on the road. Iranian state media said the killing appeared to be an assassination. Iran's Defense Minister Brig. Gen. Amir Hatami was quoted by Iran's semi-official news agency ISNA as saying Fakhrizadeh was targeted by gunfire and a Nissan vehicle explosion before a firefight ensued. Iranian Foreign Minister Zarif called the death "cowardice — with serious indications of Israeli role." Israeli Prime Minister Benjamin Netanyahu's office declined to comment to CNN. Fakhrizadeh was head of the research center of new technology in the elite Revolutionary Guards and was a leading figure in Iran's nuclear program for many years. "Terrorists murdered an eminent Iranian scientist today," Zarif said in a tweet. "This cowardice — with serious indications of Israeli role — shows desperate warmongering of perpetrators Iran calls on int'l community — and especially EU — to end their shameful double standards & condemn this act of state terror." US President Donald Trump retweeted prominent Israeli journalist Yossi Melman, who wrote: "Fakhrizadeh-Mahabadi assassinated in Damavand, east of Tehran according to reports in Iran. He was head of Iran's secret military program and wanted for many years by Mossad. His death is a major psychological and professional blow for Iran." The Chief of Staff of the Iranian Armed Forces, Maj.Gen. Mohammad Bagheri warned of "severe revenge" against "the killers" of Fakhrizadeh, state-news agency IRNA reported. "The assassination of this capable and worthy manager, although it was a bitter and heavy blow to the country's defense complex, but the enemies know that the path started by the martyr Fakhrizadeh will never be stopped," Bagheri said, according to IRNA. The Trump administration said it was closely monitoring the apparent assassination. The death "would be a big deal," a US official told CNN. Trita Parsi, the co-founder and executive vice president of the Quincy Institute for Responsible Statecraft, said it was not clear who was behind the apparent assassination, but that "there are not that many candidates." "At the end of the day the only countries that actually have the intent, the motivation and the capacity — and the capacity is really important — really reduces the number of candidates to no more than Israel and potentially the United States," he told CNN's Becky Anderson. In April 2018, Netanyahu mentioned Fakhrizadeh by name when he unveiled a nuclear archive he said Mossad agents had taken from Tehran. He called him the head of a secret nuclear project called Project Amad. "Remember that name, Fakhrizadeh," Netanyahu told reporters. — Courtesy CNN