Iranian versions of what happened have changed significantly but it appears that Fakhrizadeh was mortally wounded when his car was sprayed with bullets in the town of Absard, to the east of Tehran. During the attack a bomb in a Nissan pickup truck is also reported to have exploded.

Pictures on social media show a road strewn with wreckage and blood, and a bullet-riddled vehicle. First the defence ministry reported a gunfight between Fakhrizadeh's bodyguards and several gunmen.

Then Iranian media said the scientist had in fact been killed by a "remote-controlled machine gun" or weapons "controlled by satellite".

And on Monday, Rear Admiral Shamkhani, who heads the Supreme National Security Council, confirmed it had been a remote attack, using "special methods."

Read more: BBC News