A South Korean news agency has said that North Korea test-fired a short-range missile, a report that came shortly after the communist nation declared that it successfully conducted a nuclear test today.

North Korea today boasted that it successfully tested a nuclear weapon, sparking a barrage of global condemnation and threats of harsh sanctions over an underground blast that appeared to thrust the volatile communist state into the elite club of nuclear-armed nations.

North Korea’s potential nuclear test was equivalent to 550 tons of TNT, a state-run South Korean geological institute said, which would be far smaller than the nuclear bombs dropped on Japan in the Second World War.

North Korea said today it has performed its first-ever nuclear weapons test.