Russian President Dmitry Medvedev has banned all sales of S-300 anti-aircraft missile systems to Iran.
Russia signed a 2007 contract to sell the sophisticated systems that could boost Iran's ability to defend against air strikes. Israel and the United States have objected to the deal, and no such missiles have been delivered yet.
Mr. Medvedev's decree on Wednesday also prohibited exports of tanks, aircraft and sea vessels to Iran.
Russia has recently shown increasing frustration with Iran's policies. It has said United Nations sanctions would prevent it from delivering the S-300s to Iran.
The S-300 is capable of shooting down aircraft and missiles at ranges of over 144 km and at altitudes of about 27,432 metres.
