First shipment of Russian S-400 missile defense system hardware to Ankara started on Friday, Turkey’s National Defense Ministry said, according to Anadolu Agency.

“First batch of equipment of S-400 missile defense system, which is procured to meet Turkey’s air and missile defense need, has started to arrive at Murted Air Base in Ankara as of July 12, 2019,” the ministry said on Twitter.

Following protracted efforts to purchase an air defense system from the U.S. with no success, Ankara signed the supply contract in April 2017 to purchase the Russian S-400s.

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.

Read more:   EIB announces directions to extend activity in Azerbaijan

Turkey has urged formation of a commission to clarify any technical issues, but the U.S. has failed to respond to this proposal.