Defense Secretary Mattis: 'We'll take out' North Korean missiles to Guam

Mattis warned the U.S. will know swiftly when North Korea launches its missiles

"We'll know if it's going towards Guam within moments," he said, adding later, "We know swiftly after it's launched where it's going to land."

"Well, then it becomes an issue that we take up however the president chooses," he responded.

Mattis chose stronger words for the hostile North Korean regime during the press gaggle Monday in comparison to his words last week during an event in California.

When asked to clarify his comments on an escalation of war, Mattis said, "War is up to the president, perhaps up to Congress. The bottom line is that we will defend the country from an attack. For us, that's war. That's a war-time situation."

Mattis also pointed out that making the decision to go to war can’t be done in “advance,” given a “host of things going on,” especially since there are “allies that [they] have to consult with.”

Mattis' strong statement comes as Yonhap reports that KNCA, North Korea's state news agency, reported that Kim Jong Un was briefed today by a North Korean general on the country's plan to launch missiles toward Guam.

"Dear Supreme Leader said today that the Americans' reckless military confrontational behavior has ended up the U.S. trapping themselves with their own hands and are spending pathetic fate by weary minutes and seconds and that Dear Supreme Leader will watch such stupid American behavior for a bit longer,” the statement said.

On August 10, Mattis told reporters that a potential nuclear incident "would be catastrophic" and warned that the “tragedy of war is well-known.” Mattis looked to be opting for a more diplomatic route during the Defense Innovation Unit Experimental (DIUx) event in California, saying that he wanted to “stay right here now” in the “American effort [that] is diplomatically led.”

However, Mattis changed his tune on Monday, saying “welcome to reality” for the young troops who would be going into a wartime situation, adding that this doesn’t mean war is being declared yet.

Mattis released a harsher statement immediately following Trump’s initial “fire and fury” comments last week and North Korea’s threat to send four intermediate range missiles to Guam. The war veteran said “it must be noted that the combined allied militaries now possess the most precise, rehearsed and robust defensive...capabilities on Earth,” adding that any arms race would be “grossly overmatched by ours.”

Mattis has continuously warned North Korea of “the consequences” the rogue nation could bear in his slew of statements, despite calling for actions in a “diplomatically effective manner.”

"Korea looms large in those discussions with all those predecessors," he said.

Mattis’ comments Monday come on the heels of North Korea’s warning Saturday that the Trump administration “better talk and act properly” if it doesn’t want to meet its “tragic doom.”

“The U.S. has done all sorts of wrongs to the DPRK… but now it finds itself in an ever worsening dilemma, being thrown into the grip of extreme security unrest by the DPRK. This is tragicomedy of its own making,” North Korea said in a statement distributed through state-run media.