President Tayyip Erdogan said, Turkey will not go back on its agreement to buy S-400 missile defense systems from Russia.

In an interview, President Erdogan said it would be “immoral” for Turkey to turn back from its deal with Russia.

NATO member Turkey has repeatedly said it is committed to buying the Russian missile defense system, despite warnings from the United States that the S-400s cannot be integrated into the NATO air defense system.

The US State Department said that Washington had told Turkey that if it buys the S-400 systems, the United States will have to reassess Ankara’s participation in the Lockheed Martin F-35 fighter program.