Iranian ambassador to the UN nuclear watchdog in Vienna has condemned the International Atomic Energy Agency (IAEA) for silence over assassination of top nuclear scientist Mohsen Fakhrizadeh.

Kazem Gharibabadi told reporters on Monday that the IAEA is expected to clearly declare its stance regarding the recent act of terrorism and strongly condemn it.

“The IAEA has an immediate and primary responsibility toward the member state (Iran) that has accepted the highest level of the Agency’s inspections, has the most transparent nuclear program as it implements various commitments, but its scientists are exposed to assassination threats or are targeted by terrorists, and its nuclear facilities are exposed to aggression or are targeted with sabotage,” Gharibabadi said.

His comments came in criticism of the UN nuclear watchdog’s chief who has not only refused to condemn the Friday assassination of Fakhrizadeh, but has also warned Iran against halting the international inspections of its nuclear sites in reaction to the assassination.

Speaking to AFP, IAEA Director General Rafael Grossi emains said it is "essential to give the world the necessary and credible assurances that there is no deviation from the nuclear program to military uses.”

"We understand the distress but at the same time it is clear that no one, starting with Iran, would have anything to win from a decrease, limitation or interruption of the work we do together with them," he said.

Grossi made the remarks after the Iranian Parliament demanded that the country respond to the recent assassination of the senior nuclear scientist by restricting the United Nations' regulatory mandate regarding Iran’s nuclear program.

“Such atrocity entails an immediate and regret-inducing response,” the Iranian lawmakers said on Sunday, stressing that the best means of retaliation is through “the revival of the country’s brilliant nuclear industry by ending its voluntary adherence to the Additional Protocol” and restricting the UN nuclear watchdog's unprecedented inspection regime.

Iran undertook to adhere to the Additional Protocol of the Nuclear Non-Proliferation Treaty (NPT) as part of its 2015 nuclear agreement with world countries. Under the protocol, the International Atomic Energy Agency (IAEA), the UN nuclear watchdog, is allowed to carry out “more intrusive” inspections of the country’s nuclear work.

Iran’s nuclear activities and the deal, officially known as the Joint Comprehensive Plan of Action (JCPOA), have frequently been the target of sabotage by the United States and the Israeli regime.

The US left the JCPOA in 2018, and its allies in the accord – the UK, France, and Germany – subsequently failed to secure Iran’s interests guaranteed by the deal, under Washington’s pressure.

Two of the most recent acts of sabotage -- where the Islamic Republic strongly suspects Israel to have acted with US intelligence – include a July incident at the central Natanz nuclear site that caused material damage to the facility and the Friday assassination of nuclear expert Mohsen Fakhrizadeh.

Fakhrizadeh, the head the Defense Ministry’s Organization of Defensive Innovation and Research, was targeted in a multi-pronged terrorist attack by a number of assailants in Absard city of Tehran Province’s Damavand County.