'I Explained Everything to Biden': Erdogan Reiterates Ankara Will Buy More S-400s From Russia

Ankara's move to buy Russian-made S-400 air defence systems triggered a crisis in Turkish-US relations in 2019, when the first batch, negotiated in 2017, was delivered to Turkey. It prompted the US to kick Turkey out of the F-35 fighter programme and to sanction an entity coordinating Ankara's defence sector.