Russia is assembling its S-300 surface-to-air missile defense system to begin its shipment to Iran by 2016, the Kremlin’s top official for the arms trade says.

Speaking in an interview on Tuesday, Vladimir Kozhin, President Vladimir Putin’s aide on military-technical cooperation, added that Moscow is also modernizing some parts of the system and changing contract terms such as the pricing.

“The Iranians want them as soon as possible, and we are trying too. There is activity to prepare new legal contracts, new conditions and thus prepare systems for delivery,” Kozhin said.

He added that some of the military systems that had been intended for sale to Iran were supplied to other clients, and that some parts of other S-300 systems stored across Russia have undergone “serious modernization” with the passage of years.

Restrictions on S-300 deliveries lifted

Meanwhile, Yan Novikov, the chief executive of Russian state arms producer Almaz-Antey, confirmed the removal of all restrictions on S-300 deliveries to Tehran imposed by Moscow under the West's pressure in 2010.

He told reporters that the company would supply Iran with the advanced S-300 missile system once a commercial agreement is reached.

All restrictions have been lifted by the political authorities. When there is a contract, we will supply the system, including to Iran, Novikov said.

On April 13, Putin signed a presidential decree paving the way for the long-overdue delivery of the missile defense system to Iran.

The decision to deliver the missile system came after Iran and the P5+1 group of countries - the United States, France, Britain, China and Russia plus Germany - reached a mutual understanding on Tehran’s nuclear program in the Swiss city of Lausanne on April 2.

Moscow had banned the delivery of the S-300 system to Tehran in 2010 under the pretext that the agreement it signed with Iran in 2007 was covered by the fourth round of the UN Security Council sanctions against the country over its nuclear program. The resolution bars hi-tech weapons sales to the Islamic Republic.

Iran’s Deputy Foreign Minister for Arab and African Affairs Hossein Amir-Abdollahian said on May 25 that all issues surrounding the delivery of the S-300 system to Iran were progressing well, adding that the defense system would be delivered to Iran at the soonest opportunity possible.