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The "operation was very complex, using electronic equipment and no one was present at the scene," said the secretary of Iran's Supreme National Security Council, Rear-Admiral Ali Shamkhani.
The Rear-admiral referring to the Israeli government and its external security agency, said, “the People's Mujahedeen of Iran (MEK) were "certainly" involved, along with "the Zionist regime and the Mossad.”
"The enemy used a completely new, professional and specialized method and reached its goal," he added, without elaborating on the weaponry involved.
The secretary of Iran's Supreme National Security Council commented about the incident in an interview which was broadcasted by the state-controlled television and the Fars news agency.
Without naming sources, Fars itself claimed that the attack had been carried out with the help of "a remote-controlled automatic machine gun" mounted on a pickup truck.
Meanwhile, on Saturday, Iran's President Hassan Rouhani had accused Israel of acting as a "mercenary" for the United States by carrying out the assassination.
Iran accuses Israel of scientist's murder
According to Iran’s defence ministry, scientist Mohsen Fakhrizadeh died on Friday from his wounds in a hospital, which had in a statement said assailants targeted his car and engaged in a gunfight with his bodyguards outside the capital.
Shamkhani on the death of the scientist said that an attack was anticipated to take place at some point, as the country’s foe had singled out Fakhrizadeh as a target "for twenty years.”
"Security forces had predicted the possibility of an attack on him, even predicting the possible location of the incident," he said at the scientist's funeral in Tehran.
"Frequency of (such) news in these twenty years, the required seriousness was sadly not applied" this time, he further added.
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According to the defence minister of Iran 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."