The first shipment of the Russian-made S-400 air defense missile system has arrived at the Murted Air Base in Ankara, CNN reports citing the Turkish Defense Ministry.

Turkey's decision to purchase the equipment solidifies ties that have been developed between Russia's President Vladimir Putin and his Turkish counterpart, Recep Tayyip Erdogan, and is just the latest setback to US-Turkish relations which have seen the two NATO allies at odds over issues such as Syria.

The US has long warned that Turkey risked being blocked from receiving the advanced F-35 stealth jet due to Ankara's insistence on acquiring the Russian missiles -- a system US officials fear could be used to analyze and collect intelligence on the F-35.

A NATO official said on Friday, July 12 that: "It is up to allies to decide what military equipment they buy. However, we are concerned about the potential consequences of Turkey's decision to acquire the S-400 system."

The official added that, "interoperability of our armed forces is fundamental to NATO for the conduct of our operations and missions."

The Pentagon could formally suspend Turkey from participation in the F-35 program altogether.

Touted as the future of military aviation, the F-35 jet -- which is the most expensive weapons system in history -- is a lethal and versatile aircraft that combines stealth capabilities, supersonic speed, extreme agility and sensor fusion technology, according to its primary contractor Lockheed Martin.

The plane, which maintains stealth capabilities making it harder for enemy radars to detect, has been a favorite of President Donald Trump, who has lauded the F-35 several times for being "invisible."

The US had consistently told Turkey that the S-400 was incompatible with NATO systems.