Turkey did not inform NATO about the details of the S-400 deal with Russia, a NATO official told TASS on Wednesday.

"It is up to Allies to decide what military equipment they buy. What matters for NATO is that the equipment Allies acquire is able to operate together. Interoperability of our armed forces is fundamental to NATO for the conduct of our operations and missions. No NATO ally currently operates the S-400. NATO has not been informed about the details of any purchase," the official said commenting on Ankara’s decision to purchase the S-400 missile defense systems from Russia.

On Tuesday, Turkish President Recep Tayyip Erdogan announced that Ankara had signed the agreement to purchase the S-400 systems from Moscow, and a deposit had been paid.