There is no reason not to deliver the S-300 air defense systems to Iran, the Russian Security Council said on Sunday.
Iran struck a deal with Russia on buying the S-300 systems several years ago, but there have been repeated delays over the delivery of the anti-aircraft missiles, Xinhua reported.
"There is signed contract that we must fulfill, but supplies have not started yet," Vladimir Nazarov, deputy secretary of Russia's Security Council, told Interfax in an interview.
"This deal is not restricted by any international sanctions, because it only involves the delivery of purely defensive weapons, " Nazarov said.
"On the other hand, all of our actions must contribute to global and regional stability, respecting international law and international commitments, including those under the Non- Proliferation Treaty," he said.
Unofficial information indicates that the Russian-Iranian contract envisions the sale of S-300 anti-aircraft missiles worth some 800 million U.S. dollars.
Many experts believe Moscow has refused so far to honor the contract because of pressure from the United States and Israel, which say the delivery would significantly reinforce Tehran's air defense.
The latest version of the S-300 series is the S-300PMU2 Favorit, which has a range of up to 195 km and can intercept aircraft and ballistic missiles at altitudes from 10 meters to 27 km.
It is considered one of the world's most effective all-altitude regional air defense systems, comparable in performance to the U.S. MIM-104 Patriot systems