Earlier, Turkish President Recep Tayyip Erdogan said that Ankara will not abandon the Russian S-400 air defence systems in order to buy American Patriot anti-aircraft missile systems. Turkish Foreign Minister Mevlut Cavusoglu said in a statement that Ankara may insist that the US leave Incirlik air base if Washington goes ahead with the sanctions it has threatened in response to Turkey’s purchase of S-400 missiles.