Lee Mi-Seon, a director of the National Earthquake and Volcano Center, in Seoul, shows a map of a North Korean location during a briefing about the “artificial earthquake” in North Korea, on September 3, 2017.

:: China’s earthquake administration said on Saturday it had detected a magnitude 3.4 earthquake in North Korea that was a “suspected explosion”, raising fears the isolated state had conducted another nuclear bomb test.

The administration said in a statement on its website that the quake, which occurred around 0830 GMT, was recorded a depth of zero kilometers.

Previous quakes from North Korea have indicated nuclear tests by the reclusive state, the most recent earlier this month.

There was no immediate reaction from China’s Foreign Ministry.

S. Korea says natural quake detected

The earthquake was detected in Kilju county in North Hamgyong Province, where North Korea’s known Punggyeri nuclear site is located, according to South Korea’s meteorological agency.

The agency said it was analyzing the nature of the quake and its initial view was that it was a natural tremor because no soundwaves specific to man-made earthquakes were detected.

Seoul’s weather agency said the magnitude 3.0 earthquake was detected in North Korea on Saturday around where the country recently conducted a nuclear test, but it assessed the quake as natural.

The quake was detected in northeastern North Korea, and about 20 kilometers southeast of where the North conducted its sixth and most powerful nuclear test on Sept. 3, according to an official from Seoul’s Korea Meteorological Administration.

China’s official Xinhua news agency said the epicenter was roughly at the same place as a similar shallow earthquake on Sept. 3, which turned out to be caused by North Korea’s sixth and most powerful detonation, triggering a much stronger 6.3-magnitude quake that was felt across the border in China.

Pyongyang later said it had tested a hydrogen bomb that could be fitted onto a missile — an assertion that no foreign government has so far confirmed.

Tensions rise

Tensions have continued to rise since North Korea carried out its sixth nuclear test, prompting a new round of UN sanctions.

The move prompted global condemnation, leading the UN Security Council to unanimously adopt new sanctions that include restrictions on oil shipments.

North Korea’s Foreign Minister Ri Yong Ho, currently in New York for a United Nations meeting, warned on Thursday that Kim could consider a hydrogen bomb test of an unprecedented scale over the Pacific.

Hydrogen bombs, or H-bombs, are thermonuclear weapons far more powerful than ordinary fission-based atomic bombs, and use a nuclear blast to generate the intense temperatures required for fusion to take place.