The U.S. State Department says that Washington will not give up on using diplomacy to persuade North Korea to give up its nuclear and missile programs.
The Nuclear Safety and Security Commission said its land-based xenon detector in the northeastern part of the country found traces of xenon-133 isotope on nine occasions, while its mobile equipment off the country's east coast detected traces of the isotope four times.
"I believe what President Trump wanted to say was that, not only South Korea and the United States, but also China and Russian Federation all together need to respond very firmly against North Korea's nuclear provocations", he said.
On Wednesday, South Korea's Nuclear Safety and Security Commission said it had detected traces of radioactive xenon gas from the nuclear test.
The seismic activity, they say, is a result of North Korea's sixth nuclear test September 3.
The watchdog noted Tuesday that images appeared to show two white vehicles near the north portal of the test "and their presence could be indicative of a post-test inspection effort".
Earlier this month, South Korea's defense minister suggested it was worth reviewing the redeployment of US tactical nuclear weapons on the peninsula in order to deter threats from the North, something conservative US Sen. The latest test was said to have been a hydrogen bomb created to be mounted on a newly developed intercontinental ballistic missile that has "great destructive power", state media said following the announcement of the test. She added that the images from the North's nuclear test in 2016 did not show substantial change on the mountain's surface. "The significance of this is that it has the potential to dramatically increase the threat posed by" its ballistic missiles. "No way... A use of military force, but that would result in a second Korean war".
Others, too, have said the ground-based missiles may no longer be necessary to America's policy of deterrence, and the Trump administration has been reviewing the military's nuclear posture. "If I want to send the most compelling message, I have been persuaded that the triad in its framework is the right way to go", Mattis said. Five days later, it carried out a sixth nuclear test, sending tensions soaring over its weapons ambitions and causing global concern.
A pre-emptive strike against Pyongyang's leadership would be hard to undertake, but it's widely seen as the most realistic of the limited military options Seoul has to deny a nuclear attack from its rival.