ANKARA, Turkey (AP) — Turkey's Defense Ministry says the first shipment of a Russian missile defense system has arrived in Turkey, a development that could move the country closer to U.S. sanctions.

The ministry said the first delivery of the S-400 air defense systems arrived on Friday at an air base near the capital, Ankara.

The United States has warned Turkey it will face economic sanctions if it goes ahead with the purchase of a Russian missile defense system. It has also said Turkey won't be allowed to participate in the program to produce the high-tech F-35 fighter jets.

Turkey has refused to bow to U.S. pressure, insisting that choosing which equipment to purchase is a matter of national sovereignty.