On August 29, North Korea fired a ballistic missile which flew over Japan before breaking apart and falling into the ocean.
Experts estimated that the blast - the North's sixth - was four to 16 times more powerful than any it had set off before, with far more destructive power than the bombs dropped on the Japanese cities of Hiroshima and Nagasaki during World War II. The leaders of South Korea, Japan and the European Union immediately called for additional U.N. sanctions against the isolated, impoverished nation of 25 million people.
South Korea's presidential office also said Eui-yong spoke with U.S. counterpart H.R. McMaster for 20 minutes in an emergency phone call about an hour after the detonation. By comparison, the more powerful of the two nuclear bombs dropped by the USA on Japan during World War II had a yield of 20 Kilotons TNT. The warning arrived after the Kim Jong-un regime reportedly tested a hydrogen bomb. North Korea has made similar, unsubstantiated claims after some of its previous tests.
Trump and North Korean leader Kim Jong Un spent August trading threats of mass destruction after a USA intelligence report revealed North Korea had access to nuclear missiles.
It would not be the first time North Korea exaggerated its achievements - they wrongly claimed to have tested an H-bomb last January - but the country is not only on the right path towards achieving its ambitions, but it is doing so far quicker than anyone expected.
The unexpectedly powerful test Sunday was said to exceed in magnitude the atomic bombing of Hiroshima, Japan - the resultant shock caused momentary panic in parts of China - and Mr Trump slammed it as "very hostile and unsafe to the United States".
Hertling said that means the U.S. doesn't need to do anything drastic to counter the current North Korean threat.
Despite new threats from the Trump administration, the U.S. still has no real, practical military option on North Korea, analysts say. Mattis said they reviewed each of the United States' military options in the Asia-Pacific.
Such a move would have serious ramifications, resulting in a halt to USA trade with China, who remains its key economic partner. China has its own concerns on the Korean Peninsula and has no interest in any solution that could lead to a unified, democratic Korea.
The Chinese Foreign Ministry released a statement urging North Korea "to face up to the firm will of the global community on the denuclearization of the peninsula. stop taking wrong actions that exacerbate the situation and are not in its own interest, and return to the track of resolving the issue through dialogue". "China's government expresses resolute opposition and strong condemnation toward this", the Chinese foreign ministry said in a statement on its website.
President Trump confirmed the nuclear test..
The council announced it would be having an emergency meeting to discuss the developments.
Mr Trump also lashed out at South Korea. Estimations of the size of the explosive yield from this latest test are disputed.
His words echo those of President Trump, who took to Twitter following Pyongyang's announcement to state that appeasement would not work with North Korea.
Now, the Trump administration pledges to take action if the US or our allies are threatened. The Post said Mattis and national security adviser H.R. McMaster were among the high-ranking officials opposing the plan.
Hydrogen bombs use nuclear fusion, in which atoms fuse together, to release even greater amounts of energy. U.S. Geological Survey data showed that a magnitude-6.3 seismic event was detected Sunday in North Hamgyeong Province.
Mattis' statement does not say the USA would not strike first - it actually suggests America's military might, because it uses the word "threat" as opposed to action or attack.
"We have many military options".
North Korea's state-run television broadcast a special bulletin Sunday afternoon to announce the test.