North Korean dictator Kim Jong-un has been brutally prepared to allow his people to suffer.
The move was condemned worldwide by rival nations placing the globe on the brink of all-out war.
The secretive regime Sunday tested a hydrogen bomb that can fit on an intercontinental ballistic missile. Trump had also condemned North Korea for conducting a nuclear test that was "very hostile and unsafe to the United States".
Ever since North Korea's threats to attack the USA island territory of Guam earlier this year, South Korean, American and Japanese military forces have been ramping up an armed presence in the Pacific ocean.
The bomb was the communist state's sixth so far this year and plunged Kim's relationship with rival leaders to an all-time low.
South Korea said Monday the North is making preparations for launching another ICBM after two such test of long-distance missiles in July.
While Maj. Gen. Kyung-soo didn't reveal details about the nature of the activity or indicate when the test could take place, experts believe that North Korea may be planning the launch to coincide with the country's anniversary of its establishment in 1948.
The Asian country said it would make the U.S. "pay dearly" for the sanctions, prompting Trump to threaten to unleash "fire and fury". That would include China, which provides an economic lifeline to North Korea. He said the North could launch the missiles ahead of September 9, the anniversary of the day North Korea was founded, in a show of celebration at home and defiance to the US. He wanted a dialogue with North Korea, try to stamp out corruption, so this is his own internal politics.
U.S. monitors measured a powerful 6.3-magnitude quake near the North's main testing site on Sunday, felt in parts of China and Russian Federation, with an aftershock possibly caused by a rock collapse. "North Korea has a serious image problem in South Korea", says a 2015 survey on South Korean attitudes toward reunification by the Asian Institute for Policy Studies.
"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!" he wrote. China is the largest United States trading partner in terms of goods, and a trade war between the two nations could be devastating.
North Korea, which is thought to have six to 20 nuclear warheads, describes its weapons as a "precious sword of justice" against invaders and points out the demise of Iraqi and Libyan regimes after they gave up on nuclear arms.
Haley said North Korea's sixth nuclear test was a clear sign that "the time for half measures" from the United Nations had to end. Later, top United States military and diplomatic officials insisted that negotiations had not been taken off the table in dealing with North Korea.
Pyongyang has flaunted United Nations sanctions aimed at stopping its ballistic missile programme and recently threatened a strike on the USA territory of Guam.
US and its allies are looking to push through a new package of sanctions, including measures to restrict oil shipments to North Korea, US officials said. The Trump administration has started punishing companies for doing business with North Korea - so-called "secondary sanctions".