Rex Tillerson presses for Chinese cooperation over N Korea

US secretary of state Rex Tillerson has pushed for closer Chinese-US co-operation in dealing with North Korea's nuclear programme, in his first face-to-face talks with senior Chinese diplomats.

Mr Tillerson's visit to Beijing followed his remarks in South Korea on Friday in which he warned that pre-emptive military action against North Korea might be necessary if the threat from its weapons programme reaches a level "that we believe requires action".