US warns Turkey over purchase of Russia's S-400 missiles

A senior US State Department official on Thursday (local time) urged Turkey to denounce the Russian S-400 air defence systems, in an apparent suggestion to Ankara to get back to 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", a State Department 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.

The development comes a week after Turkish President Recep Tayyip Erdogan refused to ditch the S-400 air defence systems that Ankara has purchased from Russia, stating it is "not right", Sputnik reported.

Erdogan noted that his country is ready to buy Patriot systems from the US on favourable terms, but dismissed the US demands as meddling in Turkey's sovereign affairs.

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.

After a meeting with Erdogan on November 13, Trump told reporters that Ankara's "acquisition of the S-400 creates some very serious challenges for us," yet no agreement was reached on limiting or cancelling the purchase.

However, Erdogan had refuted Trump's attempts to convince him to walk away from the deal with Moscow, saying "We currently have a bilateral relationship with Russia. We cannot set aside our strategic relationship."

Trump's proposal was "an infringement on our sovereign rights," Turkish broadcaster NTV quoted Erdogan as saying.