South Korea’s military says it is analyzing whether North Korea has conducted its fifth nuclear test after an earthquake was reported Friday morning.
The South Korean Joint Chiefs of Staff said a magnitude 5.0 earthquake was detected at 9.30 a.m. local time near Punggye-ri, Kilju County — the same location as four other tests, the most recent of which was in January.
South Korea’s Prime Minister Hwang Kyo-ahn will be convening an emergency National Security Council at 11 a.m. local (10pET).
A US official told CNN that it looked like a nuclear test but confirmation would be dependent on seismic readings, location of the seismic event and whether it can be matched to an underground test site.
The US Air Force is expected to start flying the WC-135 Constant Phoenix Aircraft in the coming hours to take air samples and see if it can determine a nuclear event occurred.
Satellite images had shown new activity at the Punggye-ri nuclear test site in recent weeks, according to North Korea monitoring site 38North.
A small number of mining carts could be seen, as well as a new canopy which was designed to hide activity to the site, analysts said.
In January, North Korea claimed it had successfully tested a hydrogen bomb, a move that was condemned by the UN Security Council and led to punitive sanctions on the North Korean regime.
The South Korea Meteorological Administration said it believed the earthquake was artificial.
Earlier, the U.S. Geological Survey reported a 5.3 magnitude earthquake in North Korea.
USGS said the seismic activity hit 18 kilometers east north east of Sungjibaeham, North Korea, with a depth of 0 kilometers.
By Katie Hunt and KJ Kwon, CNN
CNN’s Barbara Starr contributed to this report