"SOCHI, October 22. /TASS/. Russia and Turkey will further continue cooperating in defense industry, Turkish President Recep Tayyip Erdogan said Tuesday at a press conference in Sochi following his talks with Russian leader Vladimir Putin.

"The works on S-400 [missile systems] continues, Turkey is receiving supply procurements. Currently, bilateral defense industry cooperation will resolutely continue," Erdogan stressed.

The Turkish president also announced that Ankara and Moscow "agreed to expand trading in national currencies."

In September 2017, Russia confirmed that the parties had signed the contract worth $2.5 billion to supply S-400 for Turkey. 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. The first procurement was delivered on July 12.

The United States and NATO have been making vigorous attempts to prevent Turkey from purchasing Russia's S-400 missile systems. On July 17, the White House press secretary said in a statement that Turkey’s decision to acquire Russian-made S-400 air defense missile systems rendered Ankara’s further participation in the US F-35 fighter-bombers program impossible.