Turkey's foreign minister says his country will retaliate against any possible U.S. sanctions over its deal with Russia for the purchase of the S-400 missile defense system.

Defending Ankara's purchase, Mevlut Cavusoglu told state-run Anadolu Agency on Friday that Turkey can choose its defense equipment as "an independent and free" country.

The deal with Russia has soured relations between the two NATO allies.

The United States says the S-400s are a threat to its F-35 fighter jet program and has told Turkey it would be excluded from that program. It has also warned Turkey of possible sanctions if it takes delivery of the Russian system.

Cavusoglu said Turkey "has counter-steps to take" should the U.S. impose sanctions.