The White House confirmed Wednesday that Turkey would no longer be permitted to take part in NATO's F-35 stealth fighter jet program after it purchased a Russian missile defense system.
"Unfortunately, Turkey's decision to purchase Russian S-400 air defense 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 said.
She said Washington had made "multiple" offers of its own Patriot missile defense system to Turkey, but Ankara went ahead and acquired the Russian system, running counter to a NATO pledge to avoid adopting Russian systems.
"This will have detrimental impacts on Turkish interoperability with the Alliance," she said.
She 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."
The announcement came five days after Turkey began taking delivery of the Russian missile system, shrugging off warnings from the United States and other NATO allies their it could impact their relationship.
The US action will lock out a number of Turkish manufacturers that were producing parts and components for the F-35, and block Turkey's plans to purchase some 100 of the advanced fighters.
On Tuesday, President Donald Trump declined to criticize Turkey for the S-400 purchase, falsely charging it was unfairly forced into the move by his predecessor Barack Obama.
"I've had a good relationship with President (Recep Tayyip) Erdogan," Trump told journalists.
"It's a very tough situation that they're in and it's a very tough situation that we've been placed in... With all of that being said, we're working through it -- we'll see what happens," he said.