North Korean state media on Sunday claimed Pyongyang had successfully conducted a hydrogen bomb test, AFP quoted the isolated nation’s official KCNA news agency. Earlier on Sunday, the United States Geological Survey had reported a possible explosion in North Korea, at a site where Pyongyang has detonated nuclear explosions in the past.

Pyongyang’s sixth underground test triggered a 6.3 magnitude earthquake that was felt in China’s Yanji, about 10km from North Korea’s Punggye-ri nuclear test site, The Guardian quoted South Korea’s meteorological agency. The test caused a quake five to six times more powerful than the seismic activity recorded after Pyongyang’s fifth nuclear test, AFP quoted South Korea’s weather agency.

On Saturday, North Korea had claimed it had developed an “advanced hydrogen bomb” that possesses “great destructive power”, Reuters reported. “If this event was an explosion, the USGS National Earthquake Information Center cannot determine its type, whether nuclear or any other possible type,” the statement by the US-based organisation said.

Chinese monitors reported a second earthquake after it detected an earthquake of 4.6 magnitude that could have been triggered after the rock covering the underground blast gave way, AFP reported.

South Korean President Moon Jae-In called for a National Security Council emergency meeting and Seoul’s military raised its alert level, AFP reported.

North Korea’s assertions came even as United States President Donald Trump and Japanese Prime Minister Shinzo Abe talked over the phone about the escalating nuclear crisis in South East Asia.

Pyongyang’s H-bomb

“The H-bomb, the explosive power of which is adjustable from tens of kilotons to hundreds of kilotons, is a multi-functional thermonuclear weapon with great destructive power, which can be detonated even at high altitudes for a super-powerful attack according to strategic goals,” the country’s official Korean Central News Agency said. “All components of the H-bomb were homemade, and all the processes were implemented on a Juche basis, thus enabling the country to produce as many powerful nuclear weapons as it wants,” the KCNA asserted. “Juche” is the ideology of self-reliance preached by North Korea founder Kim II-Sung.

However, North Korea provided no evidence of its claim. Pyongyang had twice in July tested intercontinental ballistic missiles that it claims have a reach of around 10,000 kilometres, thus making them capable of striking the US mainland.