North Korea's state-run KCNA news agency said the regime's "intention to build up a nuclear deterrent force is not aimed to threaten and blackmail others." Rather, the effort is aimed at reducing conventional weapons and funneling resources to programs that benefit its citizens, it said.
The statement by the North's official media marked the first time Pyongyang has publicly referred to nuclear, rather than physical, deterrence — signifying an escalation in the harsh language it routinely uses.
"If the U.S. keeps threatening the DPRK with nukes instead of abandoning its hostile policy toward Pyongyang, the DPRK will have no option but to build up a nuclear deterrent force," the official media said, using the country's official name, the Democratic People's Republic of Korea.
The United States has asked North Korea to reduce its massive deployment of conventional forces near the inter-Korean border, the world's most heavily fortified.
But North Korea has emphasized the importance it sees in using military force to stave off a possible U.S. attack in the wake of the war against Iraq. Pyongyang keeps two-thirds of its 1.1 million-strong military, the world's fifth largest, near the border.
The North's comments came as South Korean President Roh Moo-hyun repeated Monday that his country would never accept a nuclear-armed North Korea.
Addressing Japanese lawmakers at the end of his first official visit to Tokyo, Roh acknowledged that negotiating an end to the standoff over North Korea's suspected nuclear weapons program would take time.
"I am not hoping that this issue can be solved in a day or two," Roh said.
North Korea says it has the right to develop nuclear weapons to defend itself, but has never publicly said it is developing a nuclear arsenal, although Pyongyang's envoys told U.S. diplomats privately in April that the North had the bomb.
The communist stronghold has said it would give up its nuclear programs in exchange for U.S. security guarantees and economic aid, which it needs to fight the severe privation and food shortages its 22 million people suffer.
The United States says it has no plans to invade North Korea, but has not ruled out the military option.
In recent weeks, the North has escalated its anti-U.S. rhetoric, criticizing the U.S.-South Korea and U.S.-Japan summits in May.
In separate meetings with President Bush, Japanese Prime Minister Junichiro Koizumi and Roh said they agreed to seek a peaceful resolution to the crisis over North Korea's nuclear programs.
But all three leaders warned of tougher measures if North Korea escalates tensions.
Last week, a delegation of U.S. lawmakers said, after a visit to North Korea, that the North told them it has nuclear weapons and plans to build more. It also claimed it had nearly finished reprocessing more than 8,000 spent nuclear fuel rods, they said. The rods would give the communist state enough plutonium to make several atomic bombs.
North Korea has said it might consider U.S. demands for talks involving several nations, if it can meet one-on-one with the United States. Washington says talks to defuse tensions should include Russia, China, South Korea and Japan.
On Monday, KCNA denounced the United States' insistence on involving other nations in discussions to resolve the nuclear crisis.
The dispute flared in October when U.S. officials said North Korea admitted it had a clandestine nuclear program in violation of a 1994 agreement with Washington.
The United States and its allies suspended fuel shipments promised under the 1994 deal, and Pyongyang retaliated by expelling U.N. monitors, restarting frozen facilities capable of making nuclear bombs and withdrawing from the Nuclear Nonproliferation Treaty.
North Korea says it feels threatened by a combination of recent changes in U.S. policy. Since coming to office, the Bush administration has suspended Clinton-era talks, listed North Korea among the "axis of evil," adopted a doctrine of pre-emptive war and approved a missile defense system designed to nullify the North's missiles.
Last week, the U.S. and South Korea agreed on a pull-back of thousands of American troops from the border, where they may have been vulnerable to a lightning attack from the North.