Nuclear blast just the start, warns North Korea

North Korea warned last night that it has more in store after unleashing its third - and largest - nuclear test on Tuesday in a move swiftly condemned by China.

A statement from the Foreign Ministry in Pyongyang said the test was the "first response" to what it called US threats. "Second and third measures of greater intensity" would be taken if Washington continued its hostility.

China's Foreign Minister Yang Jiechi immediately summoned the North Korean ambassador Ji Jae-ryong for a formal protest warning that Beijing was "strongly dissatisfied and resolutely opposed" to the test.

Yang also told the envoy to "stop any rhetoric or acts that could worsen situations and return to the right course of dialogue and consultation as soon as possible", according to a Foreign Ministry statement.

United Nations Secretary General Ban Ki-moon and US President Barack Obama also condemned the test, which took place shortly before noon local time at the Punggye-ri test centre near North Korea's northeast border with China and Russia.

The test defied a UN move tightening sanctions against Kim Jong-un's regime three weeks ago. The UN Security Council, which met in New York on Tuesday, "strongly condemned" the nuclear test. The council statement made no direct reference to sanctions but demands for new measures were quickly made by the United States and its allies.