China and US to 'co-operate' on N Korea denuclearisation

China and the US have agreed to co-operate over the denuclearisation of North Korea, President Obama's national security advisor has said.

Speaking after a two-day summit in California, Tom Donilon told reporters that Presidents Obama and Xi Jinping had pledged to work together to achieve it, and that neither country would "accept North Korea as a nuclear-armed state".

The summit was the first meeting between the two men since Mr Xi became president in March.