Russia supplied Iran with S-300 missile systems in early 2016.

According to Tass news agency, Russia is about to supply Iran with two regimental-level S-300PMU-2 air defense missile systems worth more than $1 billion. Deliveries are scheduled to begin in January and be completed by September 2016.

Tass quoted a source in the field of military-technical cooperation as saying:

"Russia will supply Iran with two S-300PMU-2 regiments in two closely spaced batches. Each system includes a regimental command post and two battalions, each with four launch tubes. The delivery process is expected to be completed by September 2016."

S-300 air defense missile system. (Source: RIA Novosti)

The source added that the contract is worth more than $1 billion, including the cost of training 80 Iranian experts for four months to use the S-300.

The contract to supply Iran with the S-300 missile system was initially signed in 2007. However, in 2010, then-Russian President Dmitry Medvedev signed an order prohibiting the transfer of S-300 PMU 1 to Iran due to new UN sanctions.

Subsequently, Tehran sued the Russian arms export company Rosoboronexport, which had signed the contract with Iran, demanding $4 billion in compensation.

In 2015, the ban was lifted by President Vladimir Putin. Following this, Russia and Iran agreed to sign a new contract for the supply of more advanced systems.

According to Vietnam+