In a speech at Fakhrizadeh's funeral in Tehran, security chief Ali Shamkhani said the attackers "used electronic equipment" and were not present at the scene. He gave no further details.

The Iranian defence ministry initially reported that Fakhrizadeh was shot when several gunmen targeted his car.

Iran believes that Israel and an exiled opposition group used a remotely-controlled weapon to kill top nuclear scientist Mohsen Fakhrizadeh on Friday.

Israel has not commented on the claims.

Fakhrizadeh played a crucial role in Iran's nuclear programme in the early 2000s and more recently had been accused by Israel of continuing to help in the secret development of a nuclear weapon.

Iran insists that its nuclear activities are entirely peaceful./BBC