Russia's Deputy Defense Minister Yury Borisov said yesterday that Turkey reserves the right to buy more S-400 missile systems at previously set prices.

"Turkey has been given payment options in the contract for Russia's S-400 defense systems purchase," Borisov told reporters on the sidelines of the Russian-Cuban intergovernmental commission meeting in Havana.

"The clause related to the payment option comes into force following the delivery of the main batch," he added.

In September, Turkey agreed to buy two S-400s in a deal worth over $2 billion. Officials from Ankara have repeatedly said that the purchase of the S-400 systems was prompted to fulfill the country's security needs.

The S-400 missile defense system is Russia's most advanced long-range anti-aircraft missile system and can carry three types of missiles capable of destroying targets, including ballistic and cruise missiles.

Moreover, Turkey seeks to build its own missile defense systems as the deal also involves the transfer of technology and know-how. The S-400 system, which was introduced in 2007, is the new generation of Russian missile systems, and so far Russia has only sold them to China and India.