MOSCOW —  Russia's state arms export agency said Monday it is supplying Iran with defensive weapons, including surface-to-air missiles, but did not say whether they include sophisticated long-range S-300 missiles.

Iranian media reported Sunday that Russia had begun supplying the S-300s — an action Israel and the United States have aggressively opposed.

"Russia is developing military-technical cooperation with Iran in strict compliance with its international commitments stemming from nonproliferation agreements. This cooperation cannot be a source of concern for third countries," the statement said.

Rosoboronexport spokesman Vyacheslav Davydenko confirmed that S-300 missiles were considered defensive, but refused to say whether they were being supplied to Tehran.

Israel and the United States fear that, were Iran to possess S-300 missiles, it would use them to protect its first nuclear power plant now under construction at Bushehr by Russian contractors. That would make any potential military strike on the plant much more difficult.

The Interfax news agency later quoted an unnamed Russian military official as saying S-300 missiles would be delivered to Iran soon from Russian Defense Ministry warehouses.