The purchase of Russia's S-400 air defence systems by Turkey is a sovereign decision of the government in Ankara, however, Turkey must take into account that these weapons will not be compliant with NATO systems, US State Secretary Jim Mattis said.
"That's a sovereign decision for Turkey. Clearly, it will not be interoperable with NATO. So they're going to have to consider that if they go forward," Mattis told reporters on Monday.
In September, the press service of Russia's Federal Service for Military-Technical Cooperation (FSMTC) said that Moscow and Ankara had reached an agreement on the delivery of S-400 systems to Turkey. Turkish President Recep Tayyip Erdoğan said that Turkey had already put down a deposit for the S-400 systems. On September 29, Russian presidential aide Vladimir Kozhin confirmed that Turkey had made an up-front payment for the S-400s, adding that the delivery is scheduled for 2019.
In late October, NATO’s Military Committee Chairman Gen. Petr Pavel warned Turkey that there may be consequences if the country procured Russia's S-400 air defence system, adding that it will prevent Turkey from becoming part of any integrated air defence system.
