Reports about an earthquake Saturday in North Korea contained conflicting information about the scale and nature of the temblor.
South Korea's weather agency said a magnitude 3.0 earthquake was detected in North Korea and appeared to be a natural occurrence.
But Japan's Kyoto News reported that a Chinese monitoring agency determined the quake to be magnitude 3.4 and was likely caused by an explosion.
The quake occurred in the area where North Korea recently conducted a nuclear test, the South Korean agency reported.
An official from Seoul's Korea Meteorological Administration said Saturday's quake was detected in an area around Kilju, in northeastern North Korea. She said it was clear that the quake wasn't caused by an artificial explosion. She spoke on condition of anonymity, citing office rules.
The site of the quake is near where North Korea on Sept. 3 conducted its sixth and most powerful nuclear test in what it said was the detonation of a thermonuclear weapon.
Kyoto News said the temblor was detected at 4:29 p.m. local time at a depth of "0 kilometer," a strong indication of a manmade event, according to the China Earthquake Network Center.
Magnitude 3.0 or 3.4 are both smaller scale than from all of North Korea's six nuclear tests.
— October 2006: 4.3
— May 2009 : 4.7
— February 2013: 5.1
— January 2016: 5.1
— September 2016: 5.3
— Sept 2017: 6.3 (estimates vary)
The Associated Press contributed to this story.