During a press conference on Friday, the Acting Assistant to the Secretary of Defense for Public Affairs, Charles Summers announced that Turkey’s military relationship with the United States would face serious consequences if Ankara receives the Russian S-400 anti-aircraft missile systems.
"If Turkey takes the S-400s there will be grave consequences in terms of our military relations with them," he said.
Summers explained that the purchase of the S-400 missiles systems from Russia would affect “the sale of the Patriot anti-aircraft missile systems and the fifth-generation combat aircraft F-35s to Ankara." "They will not get the F-35 and the Patriot," said Summers.
On Tuesday, deputy head of the State Department press service, Robert Palladino, said that Turkey’s purchase of the S-400 from Russia could lead to a revision of Ankara’s participation in the F-35 program, the rejection of other potential arms deals in the future, and sanctions in accordance with the U.S. law "Countering America's Adversaries Through Sanctions Act." On the same day, General Curtis Scaparrotti, the Commander-in-Chief of the NATO Joint Armed Forces in Europe, stated that the Pentagon recommends barring Turkey from F-35 program if Ankara purchases S-400 from Moscow.
The negotiations between Turkey and Russia on the purchase of S-400 began in November 2016. In September 2017, Russia confirmed the conclusion of the contract, while Turkish President Tayyip Erdogan announced that he already made an advance payment for this deal. In mid-June, a military-diplomatic source told Russian TASS news agency that Russia’s defense enterprises were ordered to complete the production of S-400 anti-aircraft missile systems to be delivered to Turkey by May 2019.