The White House confirmed Wednesday that Turkey would be excluded from NATO's F-35 stealth fighter jet program after it purchased a Russian missile defence system in defiance of warnings from Western allies.
"Unfortunately, Turkey's decision to purchase Russian S-400 air defence systems renders its continued involvement with the F-35 impossible," White House spokeswoman Stephanie Grisham said in a statement.
The US-made F-35 Joint Strike Fighter "cannot coexist with a Russian intelligence-collection platform that will be used to learn about its advanced capabilities," she added.
Turkey's foreign ministry termed the move "unfair," saying in a statement that "this one-sided step neither complies with the spirit of alliance nor is it based on legitimate reasons."
Grisham said that Washington had made "multiple" offers of its own Patriot missile defence system to Turkey, but Ankara went ahead and acquired the S-400, running counter to a NATO pledge to avoid adopting Russian systems.
"This will have detrimental impacts on Turkish interoperability with the Alliance," she said.
Grisham added that the United States "still greatly values" its strategic relationship with Ankara and would "continue to cooperate with Turkey extensively, mindful of constraints due to the presence of the S-400 system in Turkey."