Russia must implement its agreement on selling S-300 long-range missile systems to Iran, military expert Never Davtyan told reporters on Saturday.

Expert in Iranian studies recalled the treaty was signed back in 2005. The deal was estimated at $800 million and Russian received the advance payment of $167 million. However, Russia postponed the deal bringing different reasons. Later Russia’s refusal was explained by eighth article of the UN Security Council resolution forbidding sales of weapons to Iran.

Davtyan said Russia used the resolution although it does not ban the sales of defense systems. The expert referred to the visit of high ranking representatives of Saudi Arabia and Israel to Russia. He considers S-300 would have changed Iran’s defense potential and would have made plans on attacking Iran unrealizable.

He believes Medvedev’s regime was weak to be pressed by the U.S. and several Arab states. Russia may become the next target after Syria and Iran but it would be very difficult to fill in the gaps of Medvedev’s foreign police, sd it may require 5-10 years.

The expert emphasized that Russia has to options: to pay $4 billion for refusing to supply S-300 or to implement the deal.