"Or it can choose membership of the worldwide community and the security and prosperity that comes with it".
The move could stoke economic tensions with South Korea, an important U.S. ally in the crisis over the North's nuclear program, the Washington Post noted late Saturday.
The latest test comes nearly exactly a year after North Korea's fifth nuclear test, which it also claimed was a hydrogen bomb.
North Korea conducted its fifth test past year in September.
Countries have also been barred from entering into ventures from North Korea.
China's Earthquake Administration said it had detected a second tremor, just after the first, of 4.6 magnitude which it termed as "a collapse". The Chinese government also put the size of the tremor at magnitude 6.3.
South Korea's presidential office immediately convened a National Security Council meeting on the issue.
Experts and officials have said North Korea could conduct its sixth nuclear test at any time, and that the reclusive country has maintained a readiness at its nuclear test site to conduct another detonation test at any time.
"North Korea has again demonstrated its complete disregard for its obligations under United Nations Security Council resolutions and for worldwide norms against nuclear testing", Brownlee said.
The bomb was created to be mounted on its newly developed intercontinental ballistic missile (ICBM), the North said.
New claims from North Korea Sunday morning that the country successfully tested a hydrogen bomb for an intercontinental ballistic missile.
While Moon's approach to North Korea hardens, talk of bringing US's tactical nuclear weapons back into South Korea has reemerged, which has always been championed by the conservatives.
Those words alone were within the usual bounds of U.S. commentary on answering North Korean aggression.
A man walks past a TV news on screen showing the images of Japanese Prime Minister Shinzo Abe, left, and U.S. President Donald Trump, right, while reporting North Korea's a possible nuclear test in Tokyo Sunday, Sept. 3, 2017.
Sunday's development comes amid heightened tensions after North Korea tested two ICBMs in July.
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