An earthquake has been detected in North Korea triggering fears that Pyongyang has conducted another nuclear test. According to the China's Earthquake Administration the earthquake measured 6.3 magnitude, The administration said there had been a massive explosion, suggesting that North Korea had carried out its sixth nuclear test. Another estimate said the earthquake was 5.2 magnitude. The authorities in Seoul also said they believed Kim Jong-un's regime may have performed a nuclear test. Only a few hours earlier North Korea has escalated tensions with a claim that it has developed a more advanced nuclear weapon with "great destructive power" capable of fitting on an intercontinental ballistic missile. The official North Korean news agency, KCNA, said the hydrogen bomb was inspected by Kim Jong-un. Pictures showed Kim in black suit examining a metal casing with two bulges. It was a "thermonuclear weapon with super explosive power made by our own efforts and technology", KCNA said, with the agency adding that "all components of the H-bomb were 100 percent domestically made". Some have questioned whether Pyongyang has a working H-bomb. North Koreas nuclear history: key moments But earlier this month, US intelligence is understood to have concluded that the rogue state has had produced a miniaturised nuclear warhead that could fit inside an ICBM. In January last year, Pyongyang boasted that it had carried out a successful underground test of a miniaturised hydrogen bomb. However western analysts dismissed the claims saying the six-kiloton yield was too low for a thermonuclear device. If North Korea's claims are true, the ability to mount a warhead on a missile would be seen as a significant escalation, creating a risk that it was preparing for an attack. Pyongyang's latest announcement came a week after North Korea filed several short range missiles into the sea between the Korean peninsula and Japan. These missiles appeared to have either failed in flight or exploded immediately. The past few months have been punctuated by Pyongyang's missile tests. Intercontinental ballistic missile test launch map Last month North Korea launched a Hwasong-12 intermediate-range ballistic missile which flew over Japan, triggering panic in the country and ratcheting up tension in the region. Earlier this month Pyongyang said it was "carefully examining" a plan to strike the US territory of Guam with missiles. Donald Trump warned that if the regime did so it would be met with "fire and fury like the world has never seen". At the same time the US has agreed to revise a treaty capping the development of South Korea's ballistic missiles. Agreement was reached between Donald Trump and his South Korean counterpart, President Moon Jae-in as Washington sought to boost South Korea's ability to defend itself against its northern neighbour. Following Pyongyang's announcement, Japanese Prime Minister Shinzo Abe spoke with Donald Trump by phone and said that in face of an "escalating" situation with North Korea that close cooperation between their countries, South Korea and China was needed.