Türkiye buys S-400 missiles from Russia; US warns of risks.

Pentagon chief James Mattis has warned of the risks of Türkiye purchasing Russia's S-400 "Triumph" air defense missile system.

Russia's S400 system.

He expressed doubts about the compatibility of the S-400 with NATO equipment at a press conference on July 14.

"The question is the compatibility of NATO systems with Russian systems? They will never be compatible," Mattis said, noting that the US Department of Defense needs to wait and see how Türkiye will utilize the Russian air defense missile system.

Regarding the question of whether the US would approve Türkiye's purchase of these systems, Mattis stated that it was Ankara's "sovereign decision."

According to Sputnik