Russia reassured Israel on Sunday that it stands by its commitment not to supply Iran with advanced S-300 anti-aircraft missiles despite an Iranian lawmaker's statement that the system "is being delivered to Iran."

"You will be the first to know about any progress or change in the matter of the missiles," Pyotr Stegny, the Russian ambassador to Israel, told top Israeli officials.

Stegny said Russia was not planning to advance the missile deal and had not yet begun to deliver the missiles. "We are adhering to the agreements we reached during Prime Minister Olmert's visit to Moscow."

Russia made its initial commitment regarding this matter to Israel during Prime Minister Ehud Olmert's October visit.

But Russia's RIA news agency last week quoted "confidential sources" as saying that Russia was fulfilling terms of an S-300 contract with Iran, and the official news agency of Iran, IRNA, reported on Sunday that Russia was supplying it with the missiles.

If this is the case, and the missiles are used to defend Iran's nuclear facilities, attacking them would be made more difficult.

"After a few years of talks with Russia ... the S-300 system is now being delivered to Iran," IRNA quoted Email Kosari, deputy head of parliament's Foreign Affairs and National Security Committee, as saying. "The delivery of this system is a display of good relations between Iran and Russia, which cannot be harmed by Israel," Kosari apparently said, adding the S-300 system would be used to defend Iran's borders.

The S-300 missile system is considered one of the most sophisticated anti-aircraft systems in the world. It includes a mobile missile launcher that fires at a rate of one missile every three to five seconds. The missiles can hit aircraft at a maximum height of about 30 kilometers, and at a distance of 150 kilometers.