In his confirmation hearing, U.S. Defense Secretary nominee Mark Esper said on Tuesday that Turkey acquiring the S-400 missile-defense system last week was “disappointing.”

“Acquisition of the S-400 fundamentally undermines the capabilities of the F-35,” he said.

“They are a NATO ally, a longstanding and capable ally,” added Esper. “It is very disheartening to see how they have drifted over the past several years.”

Also on Tuesday, U.S. President Donald Trump said that Turkey, for purchasing the S-400, will be barred from acquiring the F-35 fighter jet.

“So what happens is we have a situation where Turkey is very good with us, very good, and we are now telling Turkey that because you have really been forced to buy another missile system, we’re not going to sell you the F-35 fighter jets,” he said. “It’s a very tough situation that they’re in, and it’s a very tough situation that we’ve been placed in, the United States.”

Additionally, lawmakers on Capitol Hill say sanctions are coming against Ankara for the Friday acquisition, in addition to remarking that the United States has no choice but to sanction Turkey under the Countering America’s Adversaries Through Sanctions Act.