Donald Trump's North Korea sets tone for US-China summit

Cordelia Lynch, US Correspondent

Donald Trump, new to the world of global diplomacy, says he is willing to go it alone against an unpredictable dictator determined to build a nuclear arsenal.

North Korea has become a major and pressing security concern for his administration.

Until now, the strategy has been America, China and other nations working together to stop Kim Jong-Un.

Mr Trump now seems confident about the prospect of changing tack and going it alone without China.

At the moment, it's just mood music.

Analysts say he is trying to set the tone for the US-China summit and to build some political leverage.

He has hinted that trade could be the way in - and his recent remarks have not come out of the blue.

In March, during a trip to Asia, US Secretary of State Rex Tillerson said pre-emptive military action is an option "on the table".

Defence Secretary James Mattis has also said that the use of nuclear weapons would be met with an "overwhelming response".

But America's allies do not share the President's confidence in departing from the current approach.

Unilateral military action could risk a regional war and diplomatic pressure, while sanctions largely remain the preferred options.

For those to be effective, America needs China's help.

And it is a delicate balance. Beijing is already irked by America's decision to deploy new surface-to-air missile batteries to South Korea in the wake of the latest escalation.

But Mr Trump is agitating for a new dynamic in the region, already warning that this week's meeting with Chinese president Xi Jinping will be "difficult".

So far, his threats have not materialised - but he seems determined to get some concessions from China.

He could push for face-to-face meetings with his North Korean counterpart, but that is certainly not on the cards yet.

And unless Mr Trump has thought of something new, China and others are likely to carry on with their multilateral pressure on Kim Jong-Un.