Seoul: North Korea said its nuclear arsenal "serves as a treasured sword", amid reports the secretive state could be preparing for a third nuclear test.
Pyongyang 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 nuclear threat from the United States.
The Nuclear Non-Proliferation Treaty (NPT), a global nuclear safeguard accord, was not doing its job properly, the 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 on 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 on Thursday that another atomic weapons test would be "provocative" but said he did not have any evidence to support the South Korean report.
The situation in North Korea is being keenly monitored as Pyongyang has begun laying the ground work for the future succession of ruler Kim Jong-Il`s youngest son Kim Jong-Un.
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 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.
A group of senior Chinese military officers arrived in Pyongyang on Saturday to begin a four-day visit to North Korea, state media reported.
China`s state news agency Xinhua said the delegation led by Guo Boxiong, vice chairman of the country`s Central Military Commission, would attend events to mark the 60th anniversary of Chinese forces` entry into the Korean War.
At a recent meeting in Seoul, military leaders from 26 nations warned that the North`s nuclear programme poses "the most serious threat" to the Asia-Pacific region.
US Admiral Robert Willard, commander of the US Pacific Command, said the threat from the North`s nuclear capabilities was "widely recognised as significant not just to South Korea but the region as a whole".
"The next (nuclear) test would be a very serious matter for the international community and (South Korea)," he warned.