Israeli and Western security sources say Fakhrizadeh was instrumental in Iran's nuclear programme. The physics professor is said to have led "Project Amad", a covert programme that Iran allegedly established in 1989 to carry out research on a potential nuclear bomb.
The project was shut down in 2003, according to the International Atomic Energy Agency, though Israeli Prime Minister Netanyahu said in 2018 that documents obtained by his country showed Fakhrizadeh led a programme that was secretly continuing Project Amad's work. In a presentation, Mr Netanyahu urged people to "remember that name".