North Korea has been struck by a 3.4 scale earthquake that China says may have been caused by an explosion.
South Korea's weather agency, however, said it was examining the quake and took the view that it was a naturally occurring phenomenon.
Chinese seismic services detected the tremor, which was recorded at a depth of zero kilometres, at around 8.30 GMT on Saturday morning.
An official from Seoul's meteorological agency said it had been detected near where North Korea had recently conducted a nuclear test, but said it was clear the quake was not caused by an artificial explosion.
The head of the Comprehensive Nuclear Test Ban Treaty Organisation, Lassina Zerbo, said the blast was 50km away from previous sites.
He said the agency's analysts were "looking at unusual seismic activity of a much smaller magnitude" in North Korea.
In the past, earthquakes in North Korea have indicated nuclear tests by the nation, which is currently sparring with the United States over weapons capabilities.
The site of the tremor is close to where the regime on 3rd September claimed to have detonated a thermonuclear weapon, in its sixth and most powerful nuclear test to date.
Donald Trump later used his speech to the UN General Assembly to tell the world he would "totally destroy" North Korea if the US or its allies were threatened by its regime.
Korean leader Kim Jong Un branded the speech the "most ferocious declaration of war in history" and said he would consider the "highest level of hard-line countermeasure" in response.
