Iran’s president on Saturday accused Israel of killing a prominent Iranian scientist long suspected by the West of masterminding a secret nuclear bomb programme, state TV reported.

Iran’s clerical and military rulers have threatened revenge for Friday’s killing of Mohsen Fakhrizadeh, who Iranian media said died in hospital after assassins gunned him down in his car near Tehran.

“Once again, the evil hands of global arrogance were stained with the blood of the mercenary usurper Zionist regime,” a term for Israel, President Hassan Rouhani said in a statement, according to state TV.

“The assassination of martyr Fakhrizadeh shows our enemies’ despair and the depth of their hatred [...] His martyrdom will not slow down our achievements.”

Fakhrizadeh had long been suspected by Western, Israeli and Iranian exile foes of the Islamic Republic to have masterminded what they said was a covert atomic bomb programme. Iran has long denied seeking to weaponise nuclear energy.

He was believed to have headed what the UN nuclear watchdog and US intelligence services believe was a coordinated nuclear weapons programme in Iran, which the Islamic republic said it shelved in 2003.

He has the rare distinction of being the only Iranian scientist named in the International Atomic Energy Agency’s 2015 “final assessment” of open questions about Iran’s nuclear programme and whether it was aimed at developing a nuclear bomb.

The IAEA’s report said that he oversaw activities “in support of a possible military dimension to (Iran’s) nuclear programme” within the so-called AMAD Plan.

The death of Fakhrizadeh could provoke confrontation between Iran and its foes in the last weeks of Donald Trump’s United States presidency while complicating any effort by President-elect Joe Biden to revive the detente of Barack Obama’s presidency.