Iran has not yet decided to buy Russia's S-400 air defense systems, Iranian Deputy Defense Minister Brig. Gen. Abdolkarim Banitarafi said Thursday at the MAKS-2017 International Aviation and Space Salon.

The MAKS is held in the town of Zhukovsky in the greater Moscow Region on July 18-23.

"With regard to the equipment, we have bought S-300 systems from Russia. And regarding the S-400, we have not yet come to any decision," Banitarafi said.

Moscow agreed on supplying Tehran S-300 missile systems to Iran back in 2007, but the Russian contingent suspended the implementation of the deal in 2010 due to UN anti-Iran sanctions and resumed working on the deal in April 2015, a couple of months before the Iran nuclear deal's conclusion. On October 13, 2016, Russia completed deliveries of the batch of S-300's to Iran.

On February 15, 2016, the Russian special presidential envoy to Afghanistan said Tehran also showed interest in deliveries of Russian S-400 air defense systems, but the two countries were not currently holding any negotiations on the topic.

The S-400 is Russia's next-generation air defense system. It carries three different types of missiles capable of destroying aerial targets at a short-to-extremely-long range.