Mattis warns we 'could escalate into war very quickly' amid possible North Korean missile moves

If North Korea fires a missiles at the US, Secretary of Defense Jim Mattis told reporters on Monday that "it could escalate into war very quickly," according to Reuters' Idrees Ali.

Mattis said the US could assess "within moments" if a missile fired from North Korea was on track to hit the US territory of Guam, and that "we will take it out," in that situation.

Mattis's comments came as CNN's Will Ripley has reported a senior US defense official as telling him North Korean mobile missile launchers have been moving around, and a possible intermediate range missile launch may be in preparation.

North Korea previously threatened to launch intermediate-range Hwasong-12 missiles towards Guam in mid August, though it said it would launch them in the waters 30-40 kilometers from Guam.

Mattis's statement suggests that the US would know with a high degree of accuracy if the missiles were on track to hit Guam, which differs from North Korea's stated plan to land them near Guam.

Experts contacted by Business Insider found the prospect of North Korea carrying out its plan unlikely.