On Tuesday, a source in the Iranian Defense Ministry told Sputnik that the recent comprehensive nuclear agreement between the six world powers and Iran could allow Tehran to gain access to a more advanced air defense system than S-300.
"Negotiations are almost finished, Iran may receive a more modernized system instead of S-300", the source said.
He added that if the process of negotiations will be developing at the current pace, the air defense systems may be delivered by the year-end.
"If Iran gets the S-300 system or other modern system it will be possible to say that the sky over Iran is protected against any airstrike", the source said.
In April, Russian President Vladimir Putin lifted the ban on S-300 deliveries, shortly after the P5+1 group of international negotiators and Iran reached a framework nuclear agreement.
In mid-June, a source familiar with the situation said that Russia and Iran were in talks on resuming the implementation of the S-300 delivery contract.