GENEVA- North Korea, irked by South Korean and Japanese criticism of its nuclear test, said on Tuesday it may not support moves to curb production of nuclear bomb-making material, jeopardizing the start of global talks on the issue.

The United Nations-sponsored Conference on Disarmament is weighing a proposed package amid signs that it could break a decade-long deadlock within weeks.

North Korean diplomat An Myung Hun angrily rejected criticism from the delegations of South Korea and Japan about its latest nuclear test. It said Monday's underground explosion was a self-defense measure.

This delegation cannot rule out the probability that those statements might negatively affect the positive constellation in my capital toward the draft decision, An told the Geneva forum.

Launching negotiations on a treaty to ban production of nuclear bomb-making fissile material -- plutonium and highly-enriched uranium -- is seen as the Conference on Disarmament's top priority.

Under that deal, talks would also begin on wider nuclear disarmament and preventing an arms race in outer space.

As the forum takes all decisions by consensus, adopting the package would require approval by all 65 member states.

These include the five official nuclear powers -- Britain, China, France, Russia, the United States -- India and Pakistan, which are both nuclear-capable, and Israel, widely believed to have the Middle East's only nuclear arms.

North Korea's long-time ambassador in Geneva, Ri Tcheul, returned to Pyongyang at the weekend, diplomats said. They hoped for clarification soon on his country's position.

They could hold everything up, said a diplomatic source about North Korea. But I am still optimistic we can move in the right direction.

'GRAVE THREAT'

U.S. charge d'affaires Garold Larson was one of the few speakers at Tuesday's session not to refer to North Korea, in a speech diplomats said was crafted to protect an emerging deal.

Larson said that the package on the table was a finely balanced document which now has a solid prospect of achieving full consensus, but formal agreement had yet to be reached.

But we are close and I am gratified to state that the United States is prepared to join that consensus as soon as it is reached, under the existing text, he said.

Earlier, South Korean disarmament ambassador Im Han-tauck urged the international community to send a clear and strong message to Pyongyang.

The DPRK's nuclear test not only poses a serious threat to peace and stability on the Korean peninsula, and southeast Asia and beyond, but also represents a grave challenge to the international non-proliferation regime, Im told the talks.

Japan's envoy Sumio Tarui said the test constituted a grave threat to Japan's security and a grave challenge to the international regime aimed at preventing the spread of nuclear weapons.

China and Russia also denounced the test but called for North Korea to work with world powers to resolve the nuclear issue on the divided peninsula.

Russian ambassador Valery Loshchinin warned that North Korea's latest tests will lead to an escalation of tension in eastern Asia. It also undermined the Comprehensive Test Ban Treaty banning underground nuclear explosions.

He urged Pyongyang to pursue a policy of diplomacy instead, saying the nuclear problem on the divided peninsula could be resolved only through six-party talks linking both Koreas, China, Japan, Russia and the United States.

China's envoy said his country hopes that all parties involved will keep calm and persist in efforts to seek peaceful resolution of the problem through consultations and dialogue.

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