Minister of defence Hulusi Akar said that the S-400 systems, delivered by Russia to Turkey last year, will become fully operational in April or May this year.

Axar.az informs that, "The training of the personnel for the S-400 systems as well as the deployment of the systems are going as it has been planned. They will become operational in April or May," Hulusi Akar said as quoted by Turkiye news outlets, Sputnik reported.

Russia and Turkey signed a $2.5 billion deal for the delivery of four S-400 batteries in December 2017. The delivery of all components of the S-400 air defense missile systems to Turkey was completed last year.

Turkey, however, has faced objection from the US that says the weapon system is incompatible with NATO security standards. Ankara has insisted that the S-400 systems would not pose a threat for the alliance and resisted US pressure to cancel orders.