North Korea said its nuclear arsenal "serves as a treasured sword", amid reports the secretive state could be preparing for a third nuclear test.

The bellicose claim came amid a visit by a Chinese military delegation, as well as intense world interest after Pyongyang lay the ground work for the future succession of ruler Kim Jong-Il's youngest son Kim Jong-Un.

North Korea was "entirely right when it opted for having access to nukes", the official Korean Central News Agency (KCNA) said in a commentary, adding the communist country needed to protect itself.

The North has long justified having the weapons saying they are to counter a similar threat from the United States.

The Nuclear Non-Proliferation Treaty (NPT), a global nuclear safeguard accord, was not doing its job properly, the official commentary late on Saturday said.

"This compelled (North Korea) to pull out of the NPT and have access to nuclear deterrent legitimately in order to protect the sovereignty and security of the country," it said.

The isolated and impoverished North withdrew from the NPT in 2003.

Chosun Ilbo, South Korea's biggest-selling newspaper, reported Thursday that the North appeared to be preparing for another nuclear test, citing an unidentified government source.

US satellites had detected movements of personnel and vehicles at the site where Pyongyang carried out its first two nuclear tests in 2006 and 2009, the report said.

US State Department spokesman Mark Toner said Thursday that another atomic weapons test would be "provocative" but said he did not have any evidence to support the South Korean report.

Pyongyang said on Saturday it was willing to resume stalled six-nation nuclear disarmament talks but would not be "hasty" because the United States and some other parties were "not ready".

China, the North's sole major ally and economic lifeline, is pressing to restart the forum, which groups the two Koreas, the United States, China, Japan and Russia, and began in 2003.

But prospects for renewed negotiations have been clouded by South Korean and US accusations that the North torpedoed one of Seoul's warships in March with the loss of 46 lives, a charge Pyongyang denies.

The Chinese military delegation paid tribute to the North's late president Kim Il-Sung Sunday on the second day of a four-day trip to mark the 60th anniversary of Chinese forces' intervention in the Korean War, KCNA said.

After arriving in the capital on Saturday, Guo Boxiong, vice chairman of China's Central Military Commission, said close ties between the two countries would be handed down through the generations.

Jong-Un's status as leader-in-waiting was effectively made public after Pyongyang made him a four-star general and gave him key ruling party posts late last month.

Kim Jong-Il has visited China twice this year. The last visit, in August, was seen by many analysts as a bid by the North Korean leader for Chinese support for the dynastic succession.

Beijing fears the collapse of North Korea and resulting instability on its borders and thus provides heavy aid and trade support to its neighbour, experts say.

The South's Yonhap news agency meanwhile reported that Seoul and Washington have shelved a plan to stage a joint exercise involving a US aircraft carrier later this month in the Yellow Sea.

The exercise was cancelled over fears that it could heighten regional tensions ahead of the upcoming G20 summit in Seoul, it said.

China has bristled at the idea of a US aircraft carrier group patrolling waters near its coast.

earlier related report
S.Korea says cannot rule out possible N.Korea nuclear test
Seoul (AFP) Oct 22, 2010 - South Korea said Friday the chances of a third nuclear test by the communist North could not be ruled out, although the likelihood was low, after a report of heightened activity at its atomic sites.

The comments by Unification Minister Hyun In-Taek came as defence chiefs at an international meeting in Seoul warned that Pyongyang's atomic programme represented the greatest threat to the Asia-Pacific region.

Hyun told lawmakers that the South Korean government was "watching closely because possibilities cannot be completely ruled out," but said that the chances of an imminent atomic test were "currently low."

Chosun Ilbo, South Korea's biggest-selling newspaper, reported Thursday that the secretive communist state appeared to be preparing for a third test, citing an unidentified government source.

US satellites had detected movements of personnel and vehicles at the site where Pyongyang carried out its first two nuclear tests in 2006 and 2009, the report said.

US State Department spokesman Mark Toner said Thursday that another atomic weapons test would be "provocative" but said he did not have any evidence to support the South Korean report.

"But this hasn't changed our position vis-a-vis North Korea. We said all along that they need to adhere to their commitments and they also need to refrain from provocative actions," Toner said.

South Korean government officials also said Thursday there was no concrete evidence that Pyongyang was readying such a test, saying Seoul and its allies are closely watching developments related to the North's nuclear facilities.

The situation in the deeply impoverished state is being keenly monitored as the North has begun laying the ground work for the future succession of ruler Kim Jong-Il's youngest son Kim Jong-Un.

At a high-level defence meeting in Seoul this week, military leaders from 26 nations warned that North Korea's nuclear programme poses "the most serious threat" to the Asia-Pacific region.

They also agreed on the need to enhance cooperation in maritime security operations against the proliferation of weapons of mass destruction, said General Han Min-Koo, chairman of South Korea's Joint Chiefs of Staff (JCS).

"Participating countries reached a consensus on the fact that the North Korean nuclear programme presents the most serious threat to regional security," he told reporters Friday after the Chiefs of Defence gathering which involved 26 countries.

US Admiral Robert Willard, commander of the US Pacific Command, also said the threat from North Korea's nuclear capabilities was "widely recognised as significant not just to South Korea but region as a whole".

"The next (nuclear) test (by North Korea) would be a very serious matter for the international community and the Republic of Korea (South Korea)," he warned.

North Korea said on Saturday it was willing to resume the six-nation disarmament talks but would not be "hasty" because the United States and some other parties were "not ready".

China, the North's sole major ally and economic lifeline, is pressing to restart the six-party forum, which groups the two Koreas, the United States, China, Japan and Russia and began in 2003.

But prospects for renewed negotiations have been clouded by South Korean and US accusations that the North torpedoed one of Seoul's warships in March, a charge Pyongyang denies.