“We cannot conclusively confirm at this time the nature (natural or human-made) of the event,” the USGS said

The US Geological Survey (USGS) detected a 2.9-magnitude earthquake in area close to North Korea’s nuclear test site on Thursday evening, but is currently unable to explain the nature of the seismic event.

“This event occurred in the area of the previous North Korean Nuclear tests. The event has earthquake-like characteristics, however, we cannot conclusively confirm at this time the nature (natural or human-made) of the event,” the USGS said in a brief statement.

The epicenter of the seismic event is located approximately 25 km away from Sungjibaegam, a town close to the Punggye-ri nuclear test site, at the depth of five kilometers.

The situation on the Korean Peninsula remains tense amid Pyongyang’s active development of its missile and nuclear programs and the US-South Korean military drills. In July, North Korea carried out two tests of ballistic missiles, and on August 29 and September 15 it launched two missiles, which flew over Japan’s territory. On September 3, Pyongyang announced a successful test of a hydrogen bomb.

Washington, Seoul and Tokyo believe that Pyongyang is preparing to perform another test of a ballistic missile or even a nuclear test soon.