A senior US State Department official has urged the Turkish authorities to stop using Russian air defence systems, suggesting a radical solution to get Ankara back into the F-35 stealth fighter programme.
"There is room for Turkey to come back to the table. They know that to make this work they need to either destroy or return or somehow get rid of the S-400", the official told reporters at a briefing.
"They [Turkish authorities] know that they have the choice to move forward and the choice is to rid themselves of the S-400 so that we can move forward", adding that Washington might impose sanctions if Ankara refuses to cooperate.
Russia and Turkey signed a loan agreement for the supply of S-400 air defence systems in September 2017 that resulted in the US suspending deliveries of F-35 fighter jets to its NATO ally.
Washington refused to provide Turkey with the aircraft, claiming that the S-400 deal is incompatible with the alliance's military equipment and might compromise the operations of the new fifth-generation F-35 fighter jets. Ankara has stuck to its agreement with Russia and refused to back down.