South Korea’s Yonhap news agency quoted unnamed South Korean officials as saying it was highly likely to have been a nuclear test

South Korea’s Yonhap news agency quoted unnamed South Korean officials as saying it was highly likely to have been a nuclear test

Previous artificial earthquakes in the same area and of that magnitude have all been nuclear tests

But recent satellite imagery and intelligence has shown indicated increased activity at the Punggye-ri nuclear site, indicating a fifth test was imminent

Friday is also North Korea’s National Day, which celebrates the start of the country’s leadership regime

North Korea often uses such events as an opportunity for a show of military strength

Japanese Prime Minister Shinzo Abe said a nuclear test was a "possibility" and that Japan was closely co-ordinating with its allies

"If North Korea has conducted a nuclear experiment, we absolutely cannot condone it. We must protest adamantly."

If this test is confirmed, the biggest question is what might be done, given that sanctions were tightened after the fourth nuclear test and North Korea’s launch of a satellite, which its opponents said was really a test of a missile

China joined the condemnation but there are fault-lines in its relations with the US. China doesn’t like the plans to deploy a US anti-missile defence system in South Korea. It is also angry at condemnation of its claim to disputed islands

Increasingly, China and the United States are bumping up against each other in the region