US lawmakers and the Pentagon fear that if plugged into Turkey's integrated air defense network, the S-400 air defense missile systems, which Ankara wants to buy from Russia, could be able to pick up technical data on the F-35's capabilities and pass it to Moscow, CNN wrote.
"The concern is that the F-35 is the most advanced aircraft, the most advanced NATO aircraft, and if Turkey goes forward with the acquisition of the S-400, it will allow the Russians to collect information on how to best attack an F-35 fighter," Democratic Senator Chris Van Hollen told the broadcaster.
"It's totally nuts to hand the Russians the keys to the mission capabilities of the F-35 and allow them to try to detect and then exploit any vulnerabilities," he added.
On Thursday, Turkey received the first two F-35 jets from the US at a delivery ceremony at Fort Worth, Texas. However, the US will retain custody of the jets while Turkish pilots and maintenance crewmaintainers are being trained on the new planes at Luke Air Force Base in Arizona.
Turkey has placed orders for 30 US-made F-35A fighter jets, and intends to order 70 more as part of the Joint Strike Fighter (JSF) project, which involves 10 countries and produces various versions of the plane.
The Lockheed Martin F-35 Lightning II is a single-seat, single-engine, all-weather stealth multi-role fighter. The fifth-generation plane is designed to perform ground attack and air superiority missions.
Three hundred such planes are currently in service in the US, Britain, Israel, Italy, Norway, the Netherlands, Australia and Japan.
READ MORE: US Senate's Move to Block F-35 Supplies Won't Stop Turkey From Buying S-400 — PM