US Secretary of State Condoleezza Rice and the UN's next leader warned North Korea on Thursday not to go ahead with another nuclear test, insisting it would only lead to tougher punishment for Pyongyang.
The warnings came amid signals the impoverished regime is again ready to defy international opinion after it shocked the world by testing an atom bomb last week and then called UN sanctions a "declaration of war."
Rice was holding talks with officials in Asia, lobbying North Korea's neighbours to take a harder line on Pyongyang amid US concern it would transfer nuclear know-how to other US foes such as al Qaeda or Iran.
She was also aiming to reassure South Korea and Japan that the United States would honour security guarantees for the two nations, both under the US nuclear security umbrella.
Before leaving Tokyo for Seoul, she said another nuclear test would bring "further measures" beyond the UN sanctions imposed after the October 9 test.
She was to meet in Seoul with South Korean Foreign Minister Ban Ki-Moon, the UN Secretary General-elect, and Japanese Foreign Minister Taro Aso for crisis talks on the North, now the world's eighth declared nuclear power.
"The international community's response will be much more severe," said Ban, referring to a second test.
Ban, who takes over as UN chief at the end of the year, said a second UN resolution on the North could follow.
Separately, a Japanese government spokesman said diplomats were trying to schedule a meeting of the five nations involved in stalled disarmament talks with North Korea, but declined to confirm a date.
"We are making efforts to hold it as soon as possible," Deputy Chief Cabinet Secretary Seiji Suzuki told a news conference.
Japan's Sankei Shimbun newspaper, quoting unnamed diplomatic sources, said the five -- China, Japan, Russia, South Korea and the United States -- would meet Friday in Beijing to demand North Korea abandon its nuclear weapons.
Top Chinese diplomat Tang Jiaxuan was trying to persuade Pyongyang to join the meeting, the conservative Japanese newspaper said.
China declined comment on the report and the lead US envoy to the talks, Christopher Hill, issued a flat denial.
The UN sanctions ban all trade with the North related to weapons of mass destruction, allow for inspections of North Korean cargo and impose financial controls aimed at starving its military of funds.
The regime, which says it needs nuclear weapons to fend off a US attack, said the measures amounted to war and threatened a "merciless" response to any country trying to enforce them.
Li Gun, the deputy head of North Korea's foreign ministry, hinted a second test was on the way.
"That is natural, so we don't have to care much about this issue," he told US television network ABC. Asked if the United States should not be surprised by a second test, Li replied: "That's right, yes."
Experts say multiple tests would be expected to determine if a nuclear weapon was working properly. A South Korean lawmaker said intelligence agencies had determined the North was preparing "three or four" more tests.
Since the September 11 attacks five years ago, US President Bush has made the fight against proliferation of weapons of mass destruction a priority, and said he would not allow the North to pass them on.
"If we get intelligence that they're about to transfer a nuclear weapon, we would stop the transfer," Bush told ABC. "We will use means necessary to hold them to account."
South Korea and China do not want to take part in inspecting North Korean cargo, concerned it could aggravate the North, but US officials said Rice would press close ally South Korea to take a full part in an inspections initiative.
Seoul is also feeling pressure to scale back two joint ventures in North Korea, a tourist site and industrial complex, which have provided nearly one billion dollars to Pyongyang since 1998.
Critics say the South's money paid for the North's bomb.
A spokesman for the unification ministry said the government was considering cutting its subsidies for the tourist project, known as Mount Kumgang, but a spokesman for the prime minister denied the two projects would be shut down.
After Seoul, Rice heads on to China and then Russia.
The negotiations with North Korea have stalled since Pyongyang walked out last November to protest separate US sanctions aimed at locking it out of the international banking system.
Before its weapons test, the North said it would not return to the talks until the measures were lifted.