"Deployment of the S-400 will begin in October, the air force is studying in which regions it is better to install them," Hulusi Akar said.
The head of the military department also reiterated that the acquisition of the Russian defence systems was "not a preference for Turkey, but a necessary measure." In addition, he added that Ankara and Washington "are continuing negotiations on the possible supply of the US Patriot anti-aircraft missile systems to the republic."
Recently, US State Department spokesperson warned that Turkey may be slapped with secondary sanctions and lose access to the F-35 fighter plane if it went ahead with its plans to purchase the S-400.
Russia and Turkey penned a $2.5-billion contract on four battalions of S-400s in December 2017, with the first of the systems set to arrive later this year. Designed to stop enemy aircraft, drones, cruise and ballistic missiles, the S-400 is the most advanced mobile air defence system in Moscow's arsenal.