UPDATE 3-Erdogan says Trump can waive sanctions on Turkey for Russian defence purchase

U.S. President Donald Trump has the authority to waive sanctions on Turkey for its purchase of Russian air defence systems and should find a "middle ground" in the dispute, President Tayyip Erdogan said on Sunday.Erdogan's comments came two days after NATO member Turkey took delivery of the first consignment of advanced Russian S-400 missile defence system parts, despite warnings from Washington that the move would trigger U.S. sanctions.Broadcaster Haberturk quoted Erdogan as telling Turkish jo