As part of the Iran and Russia missile system deal, Iran will receive the S-300 long range surface-to-air missile systems by the end of this year. Confirming the agreement, Deputy Foreign Minister Mikhail Bogdanov said, "As things stand now, this topic is closed. We have reached full understanding on the matter together with our Iranian partners. The question has been fundamentally solved. The rest is just technical details," reports International Business Times. Bogdanov is also a special presidential representative for the Middle East and Africa.

The S-300 is one of the most sophisticated anti-aircraft weapons in the world, and is capable of tracking multiple planes at once and some versions have an interception range of 200 kilometers. Russia had initially agreed to sell the advanced system to Iran in 2007, but later refused, saying that it was complying with a United Nations arms embargo, reports Times of Israel.

Meanwhile U.S. officials have expressed concern as the sophisticated missile defense system might hamper Washington's ability to challenge Tehran's airspace. The advanced S-300 air defense system would mean that U.S. or Israeli warplanes would not be able to fly into Iranian airspace undetected. "We've been making very clearly our objections to any sale of this missile system to Iran, as I said, for quite some time, and we'll continue to monitor it closely," State Department spokesman John Kirby said on Tuesday, according to CNN.

Giving his views on Iran being in possession of a Russian missile defense system, Michael O'Hanlon, a defense policy expert with the Brookings Institution said, "The airspace will be more tense. It will be filled up with more radar beams if you will - invisible, and yet ever present, and they will be ... radar signals that we can't easily stop or evade," according to CNN.