The transfer of the second batch of S-400 missile defense system equipment has been completed at the Mürted Airbase in Ankara, according to a statement released by the Turkish Ministry of National Defense on Sunday, Yeni Safak reports.

Ankara received its first supply of S-400 missiles in July. The delivery of the first battery was completed on July 25.

Sensing that its protracted efforts to purchase an air defense missile system from the ally U.S. was not heading towards success, Turkey in April 2017, signed a contract with Russia to acquire the S-400 anti-missile shield.

Opposing deployment of the Russian system, U.S. officials argued that would be incompatible with the NATO systems and expose its fifth generation, the state-of-art, F-35 jet, to possible Russian subterfuge.

Turkey, however, emphasized that the S-400 would not be integrated into the NATO systems, thus had no chance to pose any threat to the alliance or its armaments.

Turkey even asked for setting up of a commission to clarify any technical issues. But U.S. has, so far, not respond to this proposal.

The S-400 system is seen as one of the most advanced missile systems in the world, capable of tracking several targets simultaneously.