Beijing: North Korea's military commander has detailed plans to fire a missile at Guam by mid August after US President Donald Trump's "fire and fury" comment showed "sound dialogue is not possible with such a guy bereft of reason and only absolute force can work on him".

The statement released by North Korean state media on Thursday morning came hours after US Secretary of Defence James Mattis warned North Korea not to invite the destruction of its people.

General Mattis said the "combined allied militaries now possess the most precise, rehearsed, and robust defensive and offensive capabilities on Earth", and North Korea's capabilities were "grossly overmatched by ours".

General Kim Rak Gyom, commander of the Strategic Force of the Korean People's Army, said North Korea was examining a plan to fire four Hwasong-12 ballistic rockets as a warning to the US. A decision on whether or not to attack would be made later by North Korean leader Kim Jong-un, he said.