A 6.5 magnitude earthquake was recorded on Sunday in North Korea near the country's known nuclear test site Punggye-ri, Yonhap news agency reported, citing South Korea's meteorological agency. The agency added that the quake appeared to have been man-made and suggested that the isolated country had conducted a sixth nuclear test.
This latest news came hours after North Korea said that it had developed an advanced hydrogen bomb that possesses "great destructive power".
However, this is not the first time. Previous tremors have been caused in the region by nuclear tests. These tests have been direct challenge to US President Donald Trump.
The US Geological Survey said that the first powerful quake measured magnitude 6.3 and was 10 km deep. It added that such a magnitude would be its most powerful detonation yet.
Several witnesses, who were in the Chinese city of Yanj that is on the border with North Korea, said that they felt a tremor that lasted roughly 10 seconds, followed by an aftershock. Meanwhile, China said that it had detected a second, 4.6 magnitude quake with near identical coordinates eight minutes later.
The hydrogen bomb report by North Korea's official KCNA news agency comes amid heightened regional tension following Pyongyang's two tests of intercontinental ballistic missiles (ICBM) in July that potentially could fly about 10,000 km (6,200 miles), putting many parts of the mainland United States within range.
Ever since North Korea tested its first missile in 2006, earthquakes triggered by such nuclear tests have gradually increased in magnitude. This indicates that Pyongyang is steadily improving the destructive power of its nuclear technology.
"The H-bomb, the explosive power of which is adjustable from tens kiloton to hundreds kiloton, is a multi-functional thermonuclear nuke with great destructive power which can be detonated even at high altitudes for super-powerful EMP (electromagnetic pulse) attack according to strategic goals," KCNA reported.
The agency also quoted the North Korean leader Kim Jong Un as saying: "All components of the H-bomb were homemade and all the processes ... were put on the Juche basis, thus enabling the country to produce powerful nuclear weapons as many as it wants."