S. Korea limits entry to border industrial park

Washington and nuclear experts have been skeptical of past North Korean Korean claims about hydrogen bombs, which are much more powerful and much more hard to make than atomic bombs.

This chart shows seismic activity in Mudanjiang, China, before and after the North Korean test.

At the height of last year’s crisis, the North had issued an ultimatum for the South to halt its “psychological warfare” or face imminent attack.

White House press secretary Josh Earnest said that the initial analysis conducted by operatives is not consistent with North Korean claims of successful h-bomb test.

Even China used unusually strong language, probably because it also appeared to have been given no warning about the test, which the North claimed – against considerable evidence to the contrary – was its first effort to detonate a hydrogen bomb.

But the explosive yield is only a fraction of what would be expected during the explosion of a hydrogen bomb, it is claimed.

The announcement was made on North Korean state TV after a 5.1 magnitude natural disaster was detected near its known nuclear test site on Wednesday. But to build a credible nuclear threat, the North must explode new nuclear devices — including miniaturized ones — so its scientists can improve their designs and technology.

This test – described by the United States as a “highly provocative act” – followed the apparently successful launch of a submarine-launched ballistic missile (SLBM) on 21 December, and a series of violent incidents along the Demilitarised Zone (DMZ), the de facto land border with South Korea, in August 2015.

President of the council, Uruguay’s UN Ambassador ElbioRosselli, said: “The members… recalled that they have previously expressed their determination to take further significant measures in the event of another nuclear test [by North Korea]”. “We strongly denounce it”.

Asia analysts said China would likely support more United Nations sanctions, even though it is North Korea’s neighbour and main ally, but within limits, for fear of destabilising what has always been a physical buffer between it and U.S.-backed South Korea.

Obama also spoke to President Park Geun-hye of South Korea to discuss options. “We must respond decisively through measures such as strong global sanctions”. After a nuclear test in 2013, the Security Council took about three weeks to agree a resolution that tightened financial restrictions and cracked down on Pyongyang’s attempts to ship and receive banned cargo.

The Republicans added North Korea to a list of what they assert are Obama’s foreign policy failures, including Syria’s civil war, the rise of Islamic State and the agreement to curb Iran’s nuclear programme.

It came as Mr Kim prepared to observe what is believed to be his 32nd birthday on Friday.

Han Min-koo, the South Korean defence minister, said the military was exploring possible responses to the latest North Korean provocation, including resuming propaganda broadcasts through loudspeakers across the Demilitarised Zone that divides the two nations. It said it will not transfer its nuclear capabilities to other parties.