The UN Security Council unanimously condemned North Korea for testing a nuclear bomb, with major powers vowing new punitive action against Pyongyang for violating the world body's resolutions.
"The members of the Security Council voiced their strong opposition and condemnation of the nuclear test conducted on 25 May 2009 by North Korea, which constitutes a clear violation of (UN) Resolution 1718," council president Vitaly Churkin of Russia told reporters following an emergency meeting of the 15-member council.
Member states decided to "immediately" begin working on a Security Council resolution to address North Korea's latest test, Churkin said, adding that they required North Korea to fulfill its obligations toward council resolutions.
Several western diplomats hinted they would seek fresh sanctions against Pyongyang under a new resolution.
"This resolution should include new sanctions in addition to those already adopted because such behavior should have a cost and a price to pay," said French Deputy Permanent Representative Jean-Pierre Lacroix.
Lacroix declined to give details on any new sanctions, which he said would be determined through UN Security Council negotiations.
The US ambassador to the United Nations, Susan Rice, said "the United States will seek a strong resolution with strong measures," calling the test "a grave violation of international law, and a threat to regional and international peace and security."
But she stopped short of mentioning possible sanctions.
"We believe it ought to be a strong resolution with appropriately strong contents, but obviously unless and until we complete the negotiation process, it is premature to say what its contents will be," Rice added.
Japan's UN ambassador, Yukio Takasu, called the nuclear test "a direct threat to the security of Japan and Asia."
He declined to provide details on the contents of the future resolution, although he rejected that it would constitute a "punishment" toward North Korea, saying the resolution would instead provide "consequences" for Pyongyang's actions.
Japan has been involved in stalled six-party talks aimed at shuttering the North's nuclear program.
Hours before the emergency session, North Korea conducted its test -- an underground blast far bigger than its first nuclear test in 2006 -- drawing stern rebukes from global leaders, with US President Barack Obama warning of "grave" danger and Israel stressing "negative implications" in the Middle East.
Even China, the secretive North's closest international ally, expressed "resolute opposition."
Compounding the frustration among world leaders, the nuclear detonation came amid reports that Pyongyang also tested a short-range missile.
UN Resolution 1718, adopted in October 2006 after North Korea's first nuclear test forbids the reclusive regime from conducting any future nuclear tests or missile launches.
The Security Council on April 13 slapped sanctions against North Korea, banning transactions and calling on UN member states to freeze the assets of three business entities of Pyongyang following its April 5 rocket launch.
In response, the North said it was quitting a six-nation nuclear disarmament pact with the United States, China, South Korea, Japan and Russia. It also said it had stopped cooperating with the International Atomic Energy Agency (IAEA) and reactivated its nuclear installations.