Photo taken on Nov. 25, 2019 shows a military base in Ankara, Turkey. Turkey on Monday and Tuesday would be testing the radar systems of Russian-made S-400 anti-missile defense systems in capital Ankara, sources from the Turkish Defense Industries Directorate told Xinhua. (Xinhua)

ANKARA, Nov. 25 (Xinhua) -- Turkey on Monday and Tuesday would be testing the radar systems of Russian-made S-400 anti-missile defense systems in capital Ankara, sources from the Turkish Defense Industries Directorate told Xinhua.

Ankara Governorate on Sunday announced F-16 fighter jets and other aircraft would perform high and low altitude tests over the capital on Monday and Tuesday.

Turkey signed a contract with Russia in April 2017 to purchase the advanced S-400 systems.

The first batch of S-400 defense systems was delivered from Russia to Turkey in July. They were deployed in Murted Air base in Ankara.

Tensions between the United States and Turkey have escalated ever since over the deal, as Washington claimed that the S-400 systems would be incompatible with the NATO system and may expose its confidential military information to Russia.

Washington has halted the delivery of F-35 fighters to Turkey as Ankara went ahead with the delivery of the S-400s.??