"The bottom line is, we will defend the country from an attack; for us [U.S. military] that is war", Mattis said.
Mattis' strong statement comes as Yonhap reports that KNCA, North Korea's state news agency, reported that "Dear Supreme Leader said today that the Americans' reckless military confrontational behavior has ended up the US trapping themselves with their own hands and are spending pathetic fate by tired minutes and seconds and that Dear Supreme Leader will watch such stupid American behavior for a bit longer".
But the report said he would watch USA actions before making a decision on "the enveloping fire at Guam".
"He said that if the Yankees persist in their extremely risky reckless actions on the Korean peninsula and in its vicinity, testing the self-restraint of the DPRK, the latter will make an important decision as it already declared", KCNA reported.
DPRK stands for the Democratic People's Republic of Korea, North Korea's official name.
Although tensions have eased in Guam, which is home to two large U.S. military installations and more than 6,000 military personnel, Tonorio said there was no change to the threat level.
But Mattis told reporters that war could break out if North Korea were to fire a missile at the United States.
"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 US would attempt to shoot down any missiles aimed at either Guam or the mainland.
Last week, the North said a plan was being drawn up to fire four missiles into the sea off Guam, where United States bombers are based. He later added that the USA would "take it out" if the missile was determined to be headed for any U.S. territory. Dai's warning was that "If North Korea would first attack South Korea and, as a result, there were full-scale arms clashes, China wouldn't aid North Korea".
Today, AP employs the latest technology to collect and distribute content - we have daily uploads covering the latest and breaking news in the world of politics, sport and entertainment. -South Korean military drills scheduled for later this month.
"I am certain the United States will respond to the current situation calmly and responsibly in a stance that is equal to ours", he said. "But clearly Secretary [of State Rex] Tillerson is out there, trying to calm the situation, trying to reach out to our allies, trying to assure that the USA mission is not to provoke a war", Town said.
"The U.S. has no interest in regime change or accelerated reunification of Korea". U.S. Secretary of State Rex Tillerson said that U.S. continues to be interested in finding a way to get to a dialogue, but that's up to Kim Jong Un.
The head of the United States military said during a visit to Beijing that it was increasingly urgent for China to step up pressure on North Korea, according to a Pentagon spokesman on Wednesday.
"A resolution of the North Korea nuclear issue by military force is completely unacceptable and the peninsula's nuclear issue must be peacefully resolved by political and diplomatic methods", Lavrov was quoted as saying. He later added that the US military is "locked and loaded" to respond to its provocations.
"They are just, legal and annual drills that are focused on defence and to curb North Korea's provocations", he told a regular briefing in Seoul. "This is tragicomedy of its own making", North Korea said in a statement distributed through state-run media.
The 1961 treaty between North Korea and China, in the meantime, has seen an important reinterpretation on the Chinese side that is seldom discussed.
"Any second Korean War would have no choice but to spread into a nuclear war", it said in a commentary.
But he also made clear that while the military was poised to protect Guam from the North Korean military threat, a declaration of war was a decision that remains with Trump and Congress.
Guam's Charfauros had previously said it would take 14 minutes for a missile fired from North Korea to reach Guam.
Michael Elleman, a Senior Fellow for Missile Defense at the International Institute for Strategic Studies, has closely monitored North Korea's capabilities for years. Trump, in turn, would consult with America's allies.