The US has ordered all US passport holders to leave North Korea by September 1.
Furthermore, Americans who want to travel to North Korea will have to obtain special validation and will only be granted in “limited circumstances”, US authorities said.
In response leader Kim Jong-un warned the US it would not be safe from destruction if it tries to attack.
One Republican said Donald Trump has told him there will be a war with North Korea if the rogue nation does not end its missile programme.
“He has told me that. I believe him,” Senator Lindsey Graham told TODAY.
“If I were China, I would believe him, too, and do something about it.”