Donald Trump has not let up in his war of words with North Korea.
The US President has said his previous warnings to Pyongyang may not have been "tough enough". It comes after he said he would unleash "fire and fury" on North Korea if it ever took military action against the US.
Markets have been rocked by the escalation in tensions between the US and North Korea this week.
Ahead of Trump's latest declaration, North Korea said in a statement issued on the Korean Central News Agency that the US "would suffer a shameful defeat and final doom if it persists in extreme military adventure, sanctions and pressure".
Pyongyang also said earlier this week that it is looking at how it might strike Guam, a US base in the Pacific.
The North Koreans said they were "carefully examining" a missile attack on the base, where strategic US bombers are located, and that a plan of action would be ready soon.
The Korean People's Army (KPA) said the US bombers "threaten and blackmail [North Korea] through their frequent visits to the sky above South Korea".
"It is a daydream for the US to think that its mainland is an invulnerable heavenly kingdom," the KPA said.