On Sunday Chinese seismological center has registered a 6.3 magnitude earthquake in North Korea that was a "suspected explosion", China's Earthquake Administration said. In a statement on its website the administration said that the tremor occured at a depth of zero kilometres.
Yonhap news agency noted that South Korea was going to hold National security council following signs of Pyongyang's nuclear test.
The Japanese government is almost sure that North Korea carried out the sixth nuclear test, local media reported, citing a diplomatic source. According to the NHK broadcaster, the Japanese government convened the National Security Council meeting from 1:34 p.m. local time (04:34 GMT) at Prime Minister Shinzo Abe's office.
"There are almost no doubts that it was a nuclear test," the source told Kyodo news agency.
According to the NHK broadcaster, the Japanese government convened the National Security Council meeting from 1:34 p.m. local time (04:34 GMT) at Prime Minister Shinzo Abe's office.
A 6.3-magnitude "possible explosion" has been detected 22 kilometers (13.6 miles) east northeast of Sungjibaegam locality in North Korea, the data of the US Geological Survey (USGS) showed Sunday.
"Possible explosion, located near the site where North Korea has detonated nuclear explosions in the past. If this event was an explosion, the USGS National Earthquake Information Center cannot determine its type, whether nuclear or any other possible type," a statement on the USGS website read.
According to the USGS, the explosion occurred at a depth of 0.0 kilometers.
Later in the day the second earthquake on scale of 4.6 was registered around North Korean test site, according to China Xinhua News.