ANKARA

Turkey on Tuesday has continued to receive components of Russian S-400 missile defense system, the National Defense Ministry said.

On Twitter, Turkey’s ministry shared a photo of a Russian plane carrying the air defense hardware at the airfield on the outskirts of the capital Ankara, and said: “The 12th plane landed on the Murted airfield.”

The delivery of components of the S-400 long range air defense system is ongoing, it added.

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.

*Writing by Nilay Kar Onum, Burak Bir and Jeyhun Aliyev