Defense Secretary Jim Mattis says the U.S. will "take out" any North Korean missile it detects is heading for American soil, including the Pacific island of Guam.

Mattis says a North Korean missile strike on the U.S. would mean war.

North Korea has said it is considering a plan to launch four ballistic missiles to land in the sea just short of Guam.

Asked how the U.S. would respond, Mattis initially declined to say.

When pressed, he said that if U.S. radars and other detection and tracking systems determine that a missile was going to fall into the sea, short of Guam, then the matter would be taken to President Donald Trump for a decision on how to respond.