The situation on the Korean peninsula spiraled toward a dangerous confrontation this weekend after North Korea tested a massive hydrogen bomb and now may be about to launch another missile.
South Korea believes the rogue regime is preparing to launch a ballistic missile, possibly a long-range intercontinental ballistic missile.
This comes after the South Korean defense ministry reported North Korea's nuclear test measured at 50 kilotons; that's 4 to 5 times more powerful than the atomic bomb the U.S. dropped on Nagasaki in World War II.
The test was so powerful it triggered an earthquake felt from Russia to China.
The detonation was the strongest ever from the North. South Korea responded with live-fire drills off its eastern coast.
Defense Secretary James Mattis repeated earlier warnings that the U.S. is prepared to use overwhelming force against the North.
"Any threat to the United States or its territories including Guam or our allies will be met with a massive military response; a response both effective and overwhelming," he said.
Texas Senator Ted Cruz joined the voices saying North Korea must be stopped.
"This step, if it is right that they have now developed a hydrogen bomb, is a serious escalation in their ability to commit mass acts of murder," Cruz said, "and it is going to call for further serious steps to prevent North Korea from using those weapons."
Sanctions and other measures have been tried for decades, but haven't stopped the North.
President Trump chided U.S. ally South Korea, tweeting,"South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work, they only understand one thing!"
North Korea analyst James Cotton of the Center for Non-Proliferation Studies believes that despite its actions, the North does not want a war.
"I don't think that North Korea is exactly ready to deploy this weapon yet," Cotton said. "North Korea knows that any sort of conflict would result in its destruction and the US and its allies know that any conflict would be very costly for them as well. So it's likely that we'll remain in this status quo stand off."
President Trump is also ramping up the pressure on North Korea's major trading partner, China.
Trump said on Twitter Sunday, "The United States is considering, in addition to other options, stopping all trade with any country doing business with North Korea."
Treasury Secretary Steve Mnuchin said, "We are going to work with our allies, we'll work with China, but people need to cut off North Korea economically, this is unacceptable behavior."
China says the threat to cut off trade with countries that deal with North Korea is "unacceptable and unfair."
The U.N. Security Council is set to hold an emergency meeting on North Korea after its powerful nuclear test added another layer of urgency for diplomats wrestling with what to do next.
When a reporter asked President Trump, "Will you attack North Korea? Trump answered. "We'll see."