A Lockheed Martin F-35 aircraft is seen at the ILA Air Show in Berlin, Germany, April 25, 2018. (Reuters photo)

ANKARA, July 18 (Xinhua) -- The U.S. decision to exclude Turkey from NATO's F-35 fighter jet program is a "unilateral" step and might bring "irreparable damage" to bilateral relations, the Turkish Foreign Ministry said Thursday.

"This unilateral move is neither related to the alliance spirit or based on legitimate foundations," the ministry said in a statement.

"It is unfair to remove Turkey, one of the partners in the F-35 program," the ministry added, rejecting Washington's claim that Turkey's purchase of the Russian S-400 system would weaken the F-35 program.

The ministry statement came after the White House confirmed the exclusion of Turkey from the F-35 program, citing Ankara's decision to purchase the S-400 air defense system as the main reason.

Moreover, the Turkish suppliers, which provide more than 900 parts for F-35, would no longer receive 9 billion U.S. dollars in projected work share over the life of the program, according to Pentagon.

Turkey has ordered more than 100 F-35 fighter jets, a handful of which had been scheduled to be delivered in the coming months.

In December 2017, Turkey signed a 2.5-billion-dollar agreement with Russia on purchasing two batteries of the S-400 system.

The first shipment of the S-400 parts arrived in Turkey on Friday.