Iran scientist 'killed by remote-controlled weapon'
Iran believes Israel and an exiled opposition group used a remote-control weapon to shoot dead top nuclear scientist Mohsen Fakhrizadeh on Friday.
Security chief Ali Shamkhani said the attackers had "used electronic equipment" when Fakhrizadeh's car was fired on east of the capital Tehran.
He was speaking at the funeral of the scientist Israel accused of secretly helping to develop nuclear weapons.
Israel has not publicly commented on the allegations of its involvement.
In the early 2000s, Fakhrizadeh played a crucial role in Iran's nuclear programme but the government insists its nuclear activities are entirely peaceful.
It has been subjected to crippling Western sanctions aimed at preventing it from developing nuclear weapons.
How did the scientist die?
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.
One Iranian report quoted witnesses as saying "three to four individuals, who are said to have been terrorists, were killed".
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".