Foreign ministers from the US, Japan and South Korea have condemned North Korea's recent nuclear test ahead of the 71stUnited Nations General Assembly scheduled to begin in New York on Monday (19 September). They discussed stepping up measures to further isolate Pyongyang.

Secretary of State John Kerry, Japanese Foreign Minister Fumio Kishida and South Korea's Yun Byung-Se met in New York on Sunday and declared that the nuclear test would not go unanswered. It will be one of the key issues to be discussed at the UN General Assembly this week, according to reports.

Kerry said that the US is committed to its defence obligations with South Korea and Japan and would not hesitate in "rolling back the provocative, reckless behavior of [the North]".

He added that the US and its allies in the region would "make it clear to a reckless dictator that all he is doing through his actions is isolating his country, isolating his people and depriving his people of genuine economic opportunity. The global community will not be intimidated and will not pull back from our obligations". He also urged Kim Jong-un to freeze nuclear missile tests and return to talks over denuclearisation.

Yun Byung-Se agreed with Kerry and referred to the North's weapons tests as a "ticking time bomb". He said, "What we see is a looming perfect storm that may not only pounce on Northeast Asia but sweep over the entire world."

In a joint statement, they said Pyongyang's disregard for UN resolutions forbidding its missile and nuclear programmes calls for even tougher international measures. "They reaffirmed that they remain open to credible and authentic talks aimed at full and verifiable denuclearization of the Democratic People's Republic of Korea," the statement read.

The US has stepped up pressure on China, the North's key diplomatic backer, to do more to rein in the isolated country. China also expressed anger over its latest nuclear test, but has not made it clear whether it would support more sanctions on the country.

Global outrage after North Korea conducts its biggest nuclear test yet Reuters