"And ... in a relatively short period you could have two, four, six other countries decide that," he said.

The effect would be "exactly the opposite of what the international community wants to have happen," Rumsfeld said. "A lower nuclear threshold, more countries with nuclear weapons, a greater likelihood that one of the countries or more might transfer those weapons to a non-state entity."

Rumsfeld's comments came 10 days after North Korea detonated its first nuclear explosion and amid fears that a second test may be in the offing.

Secretary of State Condoleezza Rice was traveling in east Asia to try to shore up support for enforcement of UN sanctions against North Korea following Pyongyang's first nuclear bomb test October 8.

In Washington, State Department spokesman Tom Casey confirmed that a senior Chinese official was visiting North Korea amid fear Pyongyang may conduct another nuclear test.

Questioned during a news briefing about the reported presence of Chinese State Councilor Tang Jiaxuan in North Korea, Casey said: "I do understand that he is, as you say, either in the process of going, or perhaps there already. I'd certainly leave it up to the Chinese government to report back on his meetings."

The senior Chinese diplomat, who held talks with Bush in Washington last week, is believed to be in the communist state, Jiji Press and Kyodo News reported, quoting unnamed sources in Beijing.

"My understanding is that his trip would be part of Chinese efforts to convince the North Koreans to comply with (UN) Resolution 1718, as well as the other relevant Security Council measures that are out there," Casey added.

US and Chinese officials have both warned North Korea against exploding another atom bomb. US media, citing unnamed US officials, has reported suspicious movement at a test site.

A US official who spoke privately added: "The Chinese have told us he was going. ... I am pretty sure that he is scheduled to have meetings in the North on Thursday."

Earlier, a Chinese foreign ministry spokeswoman said: "We have no information on that currently."

China is North Korea's top political ally and trading partner and is believed to have the most leverage over the reclusive communist state.

UN Resolution 1718, unanimously approved Saturday by the Security Council, calls on North Korea to return to negotiations about its nuclear program and imposes sanctions on the impoverished state.

Although China supported the resolution, which slapped tough sanctions on North Korea, it has shown mixed feelings about a key measure for countries to search North Korean cargo ships.

earlier related report
Fight to prevent nuclear arms race just starting: German FM
Berlin (AFP) Oct 18 - North Korea's atomic weapons test signals the start of a new battle to prevent nuclear proliferation, German Foreign Minister Frank-Walter Steinmeier said on Wednesday.

North Korea and Iran's nuclear programme -- which Tehran insists is purely for peaceful purposes -- are the two biggest threats to world peace, Steinmeier said in an interview with Stern magazine.

"Both of these provocations could awaken the desire in neighbouring countries to acquire nuclear weapons. We must prevent that, so for that reason we are not at the end of the conflict, but at the start," he said.

Steinmeier ruled out using military force to disarm North Korea.

"I don't know anyone who favours that option," he said.

Steinmeier said he was optimistic that North Korea could be coaxed back to the six-party talks aimed at persuading it to give up its nuclear ambitions in return for economic and diplomatic incentives.

Iran, he said, would also eventually see the reason in entering talks "which promise the country a way out of its isolation".

North Korea's atomic bomb test this month prompted calls in Japan for it to drop its long-held opposition to developing its own nuclear weapons.

While newly elected Prime Minister Shinzo Abe has ruled out acquiring atomic weapons, members of his ruling party have called for the option to be discussed.

Visiting Tokyo on Wednesday, US Secretary of State Condoleezza Rice called for the swift and effective implementation of UN sanctions against North Korea and reassured Washington's allies that it would defend them against attack.

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