In December 2017, Moscow and Ankara signed a loan agreement for the delivery of the S-400 air defense systems to Turkey. The first shipments of the S-400 are expected in June. In spite of the US threats to impose sanctions against Ankara, Turkish officials have said that purchasing of military equipment is a sovereign right and ruled out the possibility of abandoning plans to acquire the S-400 systems.

Washington has reportedly given Ankara a chance to either abandon the S-400 deal with Russia until the end of the first week of June or face penalties, which would include sanctions, removal from Lockheed Martin's F-35 jet program and canceling the delivery of 100 F-35 jets, Sputnik news agency reported.

Earlier in the day acting US Defense Secretary Patrick Shanahan wrote in a letter to his Turkish counterpart Defense Minister Hulusi Akar that while the US seeks "to maintain our valued relationship, Turkey will not receive the F-35 if Turkey takes delivery of the S-400".

Reporter’s code: 50101