The Democratic People’s Republic of Korea (DPRK) earlier today said that it had tested an advanced hydrogen bomb successfully. This sharp escalation comes amid increasing tensions and hostility with the US, South Korea and Japan over missile testing by the North and military exercises by the South and the US.

According to Japanese and South Korean officials, a tremor was noticed near North Korea’s test site which was ten times stronger in magnitude than earlier detonation and reached a conclusion that Pyongyang had just carried out its sixth nuclear test. However, no independent sources agreed so far that it was a hydrogen bomb. It was the DPRK’s first nuclear test since Donald Trump became president and presents a huge challenge to his unpredictable and crisis ridden presidency. Trump had just hours earlier spoken to Japanese Prime Minister Shinzo Abe on the phone about the “escalating” nuclear crisis in the area.

The DPRK announced in a statement on state media that a hydrogen bomb test was ordered by Supreme Leader Kim Jong Un and that it was a “perfect success” and a “meaningful” step with regards to completing the North’s nuclear weapons program. The warhead was made to be mated with its recently developed intercontinental ballistic missile (ICBM) according to state media that came hours after the US Geological Survey (USGS) reported a 6.3 magnitude earthquake.

An unnamed American official who observes the DPRK’s military and political developments said it was too soon to say if the test really did indeed involve the testing of a thermonuclear weapon and “much less one that could be mounted on an ICBM and re-enter Earth’s atmosphere without burning up.”

Today’s nuclear detonation comes after the North escalated tensions by testing two ICBMs in July that could potentially have a range of 10000 km and could hit parts of the continental US.

Japan reacted by saying it would increase sanctions against the North with Chief Cabinet Secretary Yoshihide Suga saying that embargoes on its oil trade would be an open option. Under Kim Jong Un, the third generation leader of the Kim dynasty, the DPRK has been trying to design a nuke compact and light enough to mate with an ICBM without sacrificing range and being ensuring survivability during atmospheric re-entry. One South Korean nuclear expert at Seoul National University said that the magnitude of today’s explosion meant it was a thermonuclear bomb test.

North Korean state media quoted Kim Jong Un saying that all parts of the thermonuclear bomb were indigenous and all the processes “were put on the Juche basis, thus enabling the country to produce powerful nuclear weapons as many as it wants.” Juche is the DPRK’s domestic ideology of self-dependence which is a combination of Marxism and ultra nationalism propagated by the founder of the DPRK Kim Il Sung. The North claims its nuclear weapons are essential for its survival against American hostility.

A thermonuclear weapon can have a thousand kilotons (KT) of explosive power, tremendously more than the 10-15 KT than the DPRK’s last nuke test was thought to have yielded which was like the bomb dropped on Hiroshima, Japan in 1945. The magnitudes of nuclear explosions have steadily increased since the first detonation in 2006 which shows increasing North Korean nuclear capabilities.

Images released by state media show Kim Jong Un observing what appears to be an hourglass shaped warhead with nuclear scientists. The design of the warhead was sharply different from the ball shaped device seen last year and seems to denote the design of a two stage thermonuclear bomb according to Lee Choon-Geun, a senior research fellow at the state run Science and Technology Policy Institute.