ANKARA, May 31. /TASS/. Turkey considers other countries’ calls against using S-400 surface-to-air missile systems purchased from Russia as unacceptable, Turkish Foreign Minister Mevlut Cavusoglu said during his visit to Athens on Monday.

"The S-400 will be 100% under our control. We sent our technical specialists [to Russia] and there will be no Russian military experts in Turkey. In this regard, we view the demands by other countries ‘for not using’ [S-400s] as inadmissible," the TV Channel TRT quoted the Turkish foreign minister as saying.

Meanwhile, US Undersecretary of State Wendy Sherman said in an interview with CNN Turk that the United States had offered Turkey an alternative to the purchase of Russian-made S-400 air defense systems. However, the US diplomat did not elaborate on it.

Russia and Turkey inked a deal in 2017 on the delivery of the Russian-made S-400 air defense system to Ankara. Turkey has been the first NATO member state to purchase the air defense missile system from Russia.

Ankara’s decision to purchase the Russian-made S-400 surface-to-air missile system infuriated the United States and NATO. The United States is not abandoning its attempts to make Turkey give up the Russian air defense system.

As Turkey has not yielded to the pressure and has said that it will not give up the S-400 system, Washington has excluded Ankara from the US program of developing the fifth-generation F-35 fighter-bomber.

The United States had been threatening Turkey with unilateral sanctions for some time already over the purchase of the S-400 air defense system but was in no hurry to take these steps out of fear of further worsening relations with a major NATO ally, while Ankara warned it would not leave the imposition of these restrictions unanswered. Washington imposed its unilateral sanctions on Ankara in December 2020.

Russia’s S-400 ‘Triumf’ (NATO reporting name: SA-21 Growler) is the latest long-and medium-range surface-to-air missile system that went into service in 2007. It is designed to destroy aircraft, cruise and ballistic missiles, and can also be used against ground installations. The S-400 can engage targets at a distance of up to 400 km and at an altitude of up to 30 km under intensive enemy fire and jamming.