Russia and Iran are advancing a contract for Moscow to supply Tehran with S-300 surface-to-air missile systems.
Tehran had signed an $800 million contract to acquire S-300s from Moscow in 2007, but Russia postponed delivery in 2010 after the U.N. Security Council imposed strict sanctions on Iran.
"The contract for the supply of S-300s to Iran was not only signed by the parties, but has entered into force," Russia's RIA Novosti quoted Rostec chief Sergei Chemezov as saying Monday while he was attending the Dubai Air Show.
Rostec is the Russian state corporation that includes Rosoboronexport, the country's arms exporting agency.
The S-300 surface-to-air missile system is capable of simultaneously hitting multiple targets, like incoming missiles and aircraft, even at high altitude. It has a range of up to 200 kilometers.