Heshmatollah Falahat-Pisheh, head of the Iranian parliament's national security and foreign policy commission, claimed that the Russian-made S-300 missile defence system, which is deployed in Syria, was "inactive" during a recent Israeli missile attack on Damascus, according to the Islamic Republic News Agency (IRNA).
Falahat-Pisheh insisted that if the S-300 systems in Syria operated correctly, the Israeli military would be unable to easily conduct airstrikes on Syria, which it conducted for two days in a row.
The remarks came after the Syrian Foreign Ministry notified the United Nations that the Israeli airstrikes were possible only with US support, and with immunity "silently" approved by some other members of the UN Security Council.
Referring to Syria, Russian Foreign Ministry Spokeswoman Maria Zakharova, in turn, urged Israel to stop "the practice of arbitrary strikes on the territory of a sovereign state".
In early October, Russia completed its delivery of new S-300 systems to Syria, including 49 units of systems-related equipment such as radars, basic target acquisition systems, command posts and four launchers.
Earlier, Moscow announced that it would provide Syria with the S-300s as part of its response to the downing of a Russian Il-20 plane with 15 military personnel on board in the Syrian port city of Latakia.
Israel has repeatedly accused Iran of having a military presence in Syria, as well as suspected attempts to build a base there. However, Tehran has strongly refuted the claims, insisting that its military presence in the country is limited to sending military advisers at Damascus' request to help fight terrorists.