A satellite-controlled machine gun with "artificial intelligence" was used in last week's assassination of a top nuclear scientist in Iran, the deputy commander of the Revolutionary Guards told local media on Sunday night.

Mohsen Fakhrizadeh was driving on a highway outside Iran's capital Tehran with a security detail of 11 Guards on November 27, when the machine gun "zoomed in" on his face and fired 13 rounds, said rear-admiral Ali Fadavi.

The machine gun was mounted on a Nissan pickup and "focused only on martyr Fakhrizadeh's face in a way that his wife, despite being only 25 centimetres (10 inches) away, was not shot," Mehr news agency quoted him as saying.

It was being "controlled online" via a satellite and used an "advanced camera and artificial intelligence(AI)" to make the target, he added.

Fadavi said that Fakhrizadeh's head of security took four bullets "as he threw himself" on the scientist and that there were "no terrorists at the scene".

Iranian authorities have blamed arch foe Israel and the exiled opposition group the People's Mujahedeen of Iran (MEK) for the assassination.

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

Various accounts of the scientist's death have emerged since the attack, with the defence ministry initially saying he was caught in a firefight with his bodyguards, while Fars news agency claimed "a remote controlled automatic machine gun" killed him, without citing any sources.

According to Iran's defence minister, Amir Hatami, Fakhrizadeh was one of his deputies and headed the ministry's Defence and Research and Innovation Organization, focusing on the field of "nuclear defence".

Meanwhile, plans by Iran to install advanced centrifuges at its main nuclear enrichment plant in Natanz are "deeply worrying", France, Germany and the UK said yesterday.

The three governments, dubbed the E3, said the plans were contrary to a 2015 agreement between Tehran and world powers that aimed to restrain Iran's nuclear programme.

The deal, officially called the Joint Comprehensive Plan of Action (JCPoA), is "the best and currently the only way to monitor and constrain Iran's nuclear programme," the three countries said.

The UN's nuclear watchdog, the International Atomic Energy Agency (IAEA) reported last month that Iran had installed and begun operating advanced centrifuges at an underground section at Natanz.

"Iran's recent announcement to the IAEA that it intends to install an additional three cascades of advanced centrifuges at the Fuel Enrichment Plant in Natanz is contrary to the JCPoA and deeply worrying," the E3 said.