The US government on Wednesday suspended Turkey’s involvement with the F-35 fighter jet program, citing concerns with Turkey’s purchase of a Russian-built missile defense system.

In a statement issued by White House press secretary Stephanie Grisham, the US government said that Turkey’s purchase of the Russian S-400 missile system presented a security risk for the American-built fighter jet and the country’s future involvement with the North Atlantic Treaty Organization (NATO). “The F-35 cannot coexist with a Russian intelligence collection platform that will be used to learn about its advanced capabilities,” the statement said. Turkey’s purchase of the S-400 system additionally “undermines the commitments all NATO Allies made to each other to move away from Russian systems,” and that it “will have detrimental impacts on Turkish interoperability with the Alliance” in the future.

NATO has not officially commented. President Donald Trump blamed Turkey’s decision to purchase the Russian missile system on former president Barack Obama during a cabinet meeting, according to an NPR report.