On Sunday, Mr Kerry is meeting his Japanese counterpart Fumio Kishida and Prime Minister Shinzo Abe in Tokyo, where he is expected to reassure Japan of America's continued support during the crisis.

BBC: Kerry hails Chinese North Korea pledge

Mr Kishida said their role was to persuade North Korea that its aggressive behaviour "will not benefit them in any way whatsoever" and that the international community had to send out this strong message.

BBC: Kerry urges North Korea to join regional dialogue

At a joint news conference with Foreign Minister Fumio Kishida, Mr Kerry said North Korea had to understand by now "that its threats and provocations are only going to isolate it further and impoverish its people even further".

BBC: Kerry urges North Korea to join regional dialogue