MOSCOW, July 19. /TASS/. The United States, which is threatening to impose sanctions on Turkey for the purchase of Russia’s S-400 surface-to-air missile systems, is thus punishing Ankara for the display of its sovereignty, Russian Deputy Foreign Minister Alexander Grushko told reporters on Friday.

"This is a US foreign policy method to punish those who display the slightest signs of their sovereignty," the senior Russian diplomat said, as he commented on the information about the US plans to impose sanctions against Turkey for the purchase of S-400 systems.