The UN Security Council has ordered tightened sanctions on North Korea over its failed rocket launch and warned of new action if the isolated state stages a nuclear test.

The 15-member council -- including the North's closest ally China and nuclear-armed Pakistan -- "strongly condemned" the launch in a statement that highlighted "grave security concerns" in Asia.

The move came as Pyongyang reportedly said it would not allow International Atomic Energy Agency inspectors to examine its nuclear programme -- a key part of a deal reached with the US in February that would have seen the transfer of thousands of tonnes of much-needed food aid to the impoverished state.

At a meeting in New York on Monday the Security Council ordered new "entities and items" to be added within two weeks to the sanctions committee list created after North Korea staged nuclear tests in 2006 and 2009.

It also ordered the sanctions committee to revise the individuals and North Korean firms subject to asset freezes under the international measures.

North Korea's UN mission made no immediate comment on the Security Council action.

US ambassador Susan Rice, the council president for April, said the sanctions committee would draw up a list of new "proliferation sensitive technology" to be banned for transfer to and from North Korea.

The United States would propose a "robust package of new designations" to the committee, Rice told reporters. This would include the names of companies linked to North Korea's ballistic missile and nuclear programs.

The council said the launch of the rocket, which disintegrated over the Yellow Sea shortly after blast off, was a "serious violation" of UN resolutions 1718 and 1874. The Security Council "strongly condemned" the act.

North Korea said its rocket launch was to put a weather satellite into orbit, but the United States and its allies said it was an attempt to test a missile launcher.

The council demanded that North Korea hold back from new launches "using ballistic missile technology," suspend "all activities related to its ballistic missile program" and keep to its promised "moratorium on missile launches."

"The Security Council expresses its determination to take action accordingly in the event of a further DPRK (North Korean) launch or nuclear test," said the statement.

Japanese and South Korean analysts and officials say satellite imagery showing preparations at the North Korean town of Punggye-ri -- where nuclear blasts were staged in 2006 and 2009 -- suggest a test could be imminent.

Rice highlighted that it was a "fact of history" that rocket test launches in 2006 and 2009 were soon followed by nuclear tests.

"Clearly the potential for that pattern to persist is one that all members of the international community are mindful of and think would be a disastrous course for the North to pursue," she said.

US Secretary of State Hillary Clinton said the broad base of the international response was significant.

"We have all agreed -- that includes China -- that there will be further consequences if they pursue another provocative action," Clinton told reporters in Brasilia when asked if China would press North Korea to avoid a nuclear test.

Seoul also welcomed the agreement and urged the North to "stop provocations that could threaten peace and security of the Korean peninsula and Northeast Asia."

"The North should clearly realise that the international community" had adopted "a resolute and unified stance on its (rocket) launch," it said, and also called for Pyongyang to honour existing UN resolutions.

Tokyo hailed the Security Council move, saying North Korea should comply with UN demands "and not conduct any further launches and nuclear tests or any further provocative actions."

North Korea appeared unbowed by the increasing diplomatic pressure, deciding to suspend talks on allowing IAEA inspectors to return to monitor the suspension of its uranium enrichment process at Yongbyon, Japan's Kyodo News reported from Seoul.

The report cited an unnamed "senior US State Department official" and came as President Barack Obama's pointman on East Asia, Kurt Campbell, was in Seoul as part of a tour of the region.

Under a much-trumpeted agreement reached in February, the US had promised 240,000 tonnes of food aid for North Korea.

In exchange, Washington had extracted promises that Pyongyang would suspend enrichment of uranium and cancel nuclear and missile tests.

Abandoning the agreement means North Korea will not feel bound by its terms -- and makes it more likely it will pursue a third nuclear test, the Yomiuri Shimbun cited sources as saying.

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