North Korea has announced that it has successfully tested a miniaturized hydrogen bomb following an “artificial seismic event” that has likely become the country’s fourth known nuclear test.

The epicenter of the jolt was located 19 kilometers (12 miles) east-northeast of Sungjibaegam, Ryanggang Province, at a depth of 10 kilometers, according to preliminary data from the US Geological Survey (USGS). Similar seismic activity in roughly the same area was recorded on February 12, 2013, prior to North Korea claiming its third successful underground nuclear test.

The “unusual” seismic activity near a “known” North Korean nuclear site seems to be of artificial origin and could be the sign of a possible nuclear test, Yonhap reported.

"The Foreign Ministry is currently holding a meeting presided over by the minister to immediately determine the situation following the reports," a ministry official said, according to the South Korean news agency.

South Korea’s intelligence agency is analyzing the probability of a fourth nuclear test having taken place, while the National Security Council is preparing to hold a meeting to discuss the issue, Yonhap reported.

Japan's chief government spokesman also said the earthquake was “likely caused” by a nuclear test, Reuters reports. Meanwhile a US defense official said the department was “looking into the reports of a possible seismic event near North Korean nuclear facilities."

According to South Korean media, Pyongyang is planning a “major” announcement around 3:30am GMT. The “special and important” statement will be delivered at noon Pyongyang time, according to state-run radio.

(RT)