Korea ready to conduct another nuclear test

According to the Associated Press, Moon did not offer evidence to back the claim, merely saying South Korea and US intelligence authorities believe North Korea has the ability to detonate another atomic device anytime.

South Korean and USA intelligence officials believe the North has the ability to detonate another nuclear blast anytime, said Ministry of National Defense spokesman Moon Sang-gyun.

South Korea's defense ministry warned Monday that North Korea could conduct another nuclear test at any time.

Ministry spokesman Moon Sang-Gyun said: "An additional test could be conducted in a tunnel that branches off from the second tunnel or in the third tunnel, where preparations have been completed".

The North also vowed to increase its nuclear strike force "in quality and in quantity".

Since Friday, Chinese state media have repeatedly linked North Korea's latest nuclear test to the American deployment of a high-altitude missile defense system in South Korea, which China has long opposed.

After North Korea's nuclear test on Friday, South Korea unveiled its plan of tackling Pyongyang if there was any threat perception.

Officials said the KMPR would be put into effect either if the South Korean military sees any sign of imminent North Korean use of nuclear arms "or in case of a war".

The details of the operation came to light after the South Korean Defence Ministry unveiled the Korea Massive Punishment and Retaliation (KMPR) plan in front of the National Assembly in response to the latest nuclear test by North Korea.

It did not elaborate on what activities had been detected at the test site.

Another KCNA report yesterday said North Koreans were "delighted" by the nuclear test.

World leaders have lined up to condemn the blast, which was North Korea's second this year and likely it's most powerful to date.

The yield from Friday's test was estimated at 10 kilotons, nearly twice as much as the one Pyongyang conducted only eight months earlier.

She was responding to calls by President Barack Obama for China to tighten up sanctions against Kim Jong Un's regime prior to its fifth - and biggest - nuclear test last week.

U.S. Forces in Korea, meanwhile, postponed a flyover of two supersonic bombers - intended as a show of force - due to unfavorable weather conditions.

The BBC's Stephen Evans in Seoul says it is unlikely to happen immediately, as Pyongyang's scientists will want to study the results of the recent test, but a sixth test could be weeks or months away.