“The decision is an unfortunate development,” the PM told reporters.

“Turkey is not without alternatives. Such attempts are regrettable and goes against the soul of strategic partnership,” Yildirim said.

Yildirim’s comments came after the U.S. Senate on June 18 passed a $716 billion defense policy bill including an amendment prohibiting sales to Turkey of F-35 Joint Strike Fighter jets made by Lockheed Martin Corp.

The Republican-controlled Senate voted 85-10 for the annual National Defense Authorization Act, or NDAA, which authorizes U.S. military spending but is generally used as a vehicle for a broad range of policy matters, Hurriyet daily reported.

According to the NDAA, U.S. President Donald Trump should certify that Turkey does not threaten NATO, purchase defense equipment from Russia or detain U.S. citizens.

Senators included the legislation because of the imprisonment of U.S. pastor Andrew Brunson in Turkey’s Aegean province of Izmir on terror charges and Turkish government’s decision to purchase S-400 air defense system from Russia.

The amendment claimed that purchasing the S-400 system from Russia increases tensions and risks to the NATO alliance.

The U.S. Defense Ministry is supposed to prepare a report on relations with Turkey in 60 days. Any sales of F-35 and F-16 fighters, Patriot air defense systems, and military helicopters by Pentagon to Turkey will be blocked until the report is submitted to the Congress committees.

Reporter’s code: 50101