“The first batteries will be delivered towards the end of the next year,” Mevlut Cavusoglu told reporters in Brussels, where he is attending a NATO summit.

The Turkish FM said in addition to the US, other NATO member states have questioned the purchase but said this must end.

“We can understand the technical part. For example, it is normal for them to ask whether the S-400 recognizes NATO, NATO systems or allies as an enemy. We are also sensitive to this issue,” he said.

“We lay down our conditions in this regard when making the purchase,” he added.

Last December, Turkey announced it had concluded an agreement with Russia for the purchase of two S-400 systems by early 2020.

This April both parties agreed on the early delivery of the systems.

The S-400 is Russia’s most advanced long-range anti-aircraft missile system, with the ability to carry three types of missiles capable of destroying targets, including ballistic and cruise missiles.

Cavusoglu also rebuffed claims that Turkey is turning away from NATO.

“If our NATO allies were to meet these needs of ours, we would get [the missile systems] from them; we gave them priority,” he said.

Reporter’s code: 50101