The killing of Iran's top nuclear scientist Mohsen Fakhrizadeh last month was carried out remotely with artificial intelligence and a machine gun equipped with a "satellite-controlled smart system," an Islamic Revolutionary Guard Corps commander told Tasnim News Agency on Monday.

"No terrorists were present on the ground... Martyr Fakhrizadeh was driving when a weapon, using an advanced camera, zoomed in on him," Tasnim, a semi-official agency, quoted Ali Fadavi, the deputy commander of Iran's Revolutionary Guards, as saying in a ceremony on Sunday.

"The machine gun was placed on a pick-up truck and was controlled by a satellite."

Fadavi spoke after Iranian authorities said they had found "clues about the assassins," though they have yet to announce any arrests. Shortly after the killing, witnesses told state television that a truck had exploded before a group of gunmen opened fire on his car.

"Some 13 shots were fired at martyr Fakhrizadeh with a machine gun controlled by satellite... During the operation artificial intelligence and face recognition were used," Fadavi said. "His wife, sitting 25 centimetres away from him in the same car, was not injured."

Last week, Ali Shamkhani, Secretary of the Supreme National Security Council of Iran, said the killing was carried out with "electronic devices" with no people on the ground.

Iran has blamed Israel for the assassination of Fakhrizadeh, who was seen as the mastermind of a covert Iranian program to develop nuclear weapons capability. Tehran has long denied any such ambition.

Israel has neither confirmed nor denied responsibility for the killing, and one of its officials suggested that the Tasnim report of the tactics used was a face-saving gambit by Iran.

Various accounts of the scientist's death have emerged since the attack.

Iranian State-run Press TV, IRBR, had previously said "made in Israel" weapons were found at the scene.

Iranian Defence Ministry initially said Fakhrizadeh was caught in a firefight with his bodyguards, while Fars news agency claimed "a remote controlled automatic machine gun" killed Fakhrizadeh.

Experts and officials told Reuters last week Fakhrizadeh's killing exposed security gaps that suggest its security forces may have been infiltrated and that Tehran was vulnerable to further attacks.

Since 2010, five such high-profile scientists have died in mysterious incidents in Iran. They include Masoud Ali Mohammadi and Majid Shahriari, who were both killed in remote-controlled bombs attached to motorcycles in 2010 and 2012 respectively.

Darioush Rezaeinejad, who was connected to the nuclear program, was shot dead by gunmen on a motorcycle in July 2011.

Chemist and the director of the Natanz facility Mostafa Ahmadi Roshan became the next victim a year later.

(With input from agencies)