Trump urges UN member states to isolate Kim govt until it ceases its hostile behavior

US President Donald Trump warned on Tuesday that the United States will be forced to "totally destroy" North Korea unless Pyongyang backs down from its nuclear challenge, mocking North Korean leader Kim Jong Un as a "rocket man" on a suicide mission.

Loud murmurs filled the green-marbled UN General Assembly hall when Trump issued his sternest warning yet to North Korea, whose ballistic missile launches and nuclear tests have rattled the globe.

Unless North Korea backs down, he said, "We will have no choice than to totally destroy North Korea."

"Rocket man is on a suicide mission for himself and his regime," he said.

He urged United Nations member states to work together to isolate the Kim government until it ceases its "hostile" behavior.

A junior North Korean diplomat remained in the delegation's front-row seat for Trump's speech, the North Korean UN mission said.