Key points

:: G20 meeting of world leaders begins in Buenos Aires



:: President Putin greets Saudi crown prince with enthusiastic handshake



:: Theresa May tells prince action needed to stop 'deplorable incident' like Khashoggi murder happening again

:: PM urges 'full transparency' over killing; also calls for 'urgent need' to end Yemen war

:: Saudi media say Trump and prince had a friendly meeting, but president says it was just pleasantries

:: Donald Trump cancels meeting with Vladimir Putin, blaming hostilities in Ukraine