Defense Secretary James Mattis said Monday if North Korea attacks the U.S., it could lead to war.
"If they fire at the United States, it could escalate into war very quickly," Mattis told reporters, adding that should North Korea pursue military action, the U.S. would attempt to shoot down any missiles aimed at either Guam or the mainland.
The top Pentagon official said the U.S. could assess "within moments" whether a missile was fired from North Korea and that "we will take it out" in that situation.
While Mattis stressed that his statement should not be read as a promise of war, the military would defend the country, and for them, "that's war."
"You don't shoot at people in this world unless you bear the consequences."
Last week, President Donald Trump also warned North Korean leader Kim Jong-un that he “will truly regret it” if he continues to threaten the U.S. and its allies.
"Military solutions are now fully in place, locked and loaded, should North Korea act unwisely," he said on Twitter before retweeting Pentagon photos of B1 bombers that are said to be key to U.S. plans to strike the North.
North Korea threatened to shoot four missiles into the sea off Guam following heated exchanges with the U.S. over Pyongyang’s nuclear weapons program.
Its state-run news agency reported that North Korea's army "will complete its plan to hit Guam before mid-August.