Turkey continued on Thursday to receive components of Russian S-400 missile defense systems.
Delivery of the long-range air defense hardware continued, with 15 shipments having so far landed at the Mürted Air Base in the capital Ankara over the past week.
The first shipment was delivered last Friday.
Following protracted efforts to purchase an air defense system from the U.S. with no success, Ankara signed a contract in 2017 to purchase the S-400s from Russia.
U.S. officials urged Turkey to buy U.S. Patriot missiles, arguing the Russian system would be incompatible with NATO systems and expose the F-35s to possible Russian subterfuge.
Turkey, however, emphasized the S-400 would not be integrated into NATO systems and would not pose a threat to the alliance.
It has urged the formation of a commission to clarify any technical issues, but the U.S. has failed to respond to Turkey's proposal.
The U.S. threatened sanctions over the purchase, with Turkey responding that any sanctions would be met in kind.
On Wednesday, Washington announced it was removing Turkey from the joint program F-35 stealth fighter jet program, following through on threats to do so over Ankara's purchase of the Russian S-400 anti-air system.
Deliveries are set to continue until April 2020.
