US President Donald Trump has said Saudi Arabia could be behind the disappearance of missing journalist Jamal Khashoggi and warned Washington would inflict "severe punishment" if he was murdered.

WASHINGTON, July 30, 2017 (AFP) - US President Donald Trump warned Saturday that he would "no longer" allow China to "do nothing" on North Korea, after the belligerent hermit state launched an intercontinental ballistic missile test.