Iran's top nuclear scientist, Mohsen Fakhrizadeh, was assassinated in Tehran, Iran on November 27, 2020. Fakhrizadeh was believed to be the primary force behind Iran's covert nuclear program for many decades. The New York Times reported that Israel's Mossad was behind that attack and that Mick Mulroy, the former Deputy Defense Secretary for the Middle East said the death of Fakhirizadeh was “a setback to Iran’s nuclear program" and he was also a senior officer in the Islamic Revolutionary Guard Corps, and that “will magnify Iran’s desire to respond by force.” Following the assassination, Iran begun to enrich uranium with a purity percentage of 20 in an underground facility.