BELGRADE, October 20. /TASS/. Russian Deputy Prime Minister Yuri Borisov believes that the possibility of Russia and Turkey signing another contract on sales of Russian-made surface-to-air missile systems to Ankara is very high.

"I think the possibility is high, they have this option and they are entitled to use it," he told reporters during a visit to Serbia.

When asked whether Russia and Turkey discussed the sales of Russia’s Su-35 and Su-57 fighter jets to Ankara, Borisov said Turkish leader Recep Tayyip Erdogan demonstrated "keen interest during the MAKS air show."

"Possibly, they will make a choice in favor of our combat aviation, nothing can be ruled out," he said.

The first reports about the talks between Russia and Turkey on the deliveries of S-400 air defense missile systems to Ankara emerged in November 2016. Russia confirmed in September 2017 that the relevant contract worth $2.5 billion had been signed. Under the contract, Ankara will get a regiment set of S-400 air defense missile systems (two battalions). The deal also envisages partial transfer of production technology to the Turkish side.

Turkey is the first NATO member state to purchase such air-defense missile systems from Russia. The deliveries of S-400 air defense systems to Turkey began on July 12, 2019.

The United States and NATO have been making attempts to prevent Turkey from purchasing Russia's S-400 missile systems. Washington has warned on many occasions that it may impose sanctions on Turkey, if Ankara presses ahead with the S-400 deal.

The S-400 ‘Triumf’ is the most advanced long-range air defense missile system that went into service in Russia in 2007. It is designed to destroy aircraft, cruise and ballistic missiles, including medium-range missiles, and can also be used against ground installations. The S-400 can engage targets at a distance of 400 km and at an altitude of up to 30 km.