The ambassador Kwon Sung-chol made the remarks on Friday at a ceremony marking 50 years of diplomatic ties between North Korea and Cuba, the same day that Pyongyang said it was open to returning to nuclear disarmament negotiations.
"If Washington and Seoul try to create a conflict on the Korean peninsula, we will respond with a holy war on the basis of our nuclear deterrent forces," Kwon said, according to China's Xinhua news agency on Saturday, in a story datelined Havana.
"Our government will strive for the denuclearization of the peninsula and the establishment of a lasting peace as the beginning of the reunification process of the two Koreas," said Kwon.
Washington and Seoul have said Pyongyang must abandon its nuclear weapons development, but have not threatened to attack the poor and isolated North.
North Korea's number two leader, Kim Yong-nam, told visiting former US President Jimmy Carter that the reclusive state wanted to resume six-way nuclear disarmament talks, the North's state news agency said on Friday.
The North's leader, Kim Jong-il, appears to be visiting China in a secrecy-shrouded trip that analysts say appears intended to line up Beijing behind his succession plans. (Editing by Ron Popeski)
Amid Pyongyang's threats, China is lobbying neighbors to sign up to a road map for renewed nuclear disarmament talks with North Korea, whose leader Kim Jong-il is apparently visiting China.
The details of Beijing's plan for restarting stalled six-party nuclear talks came from a South Korean diplomatic source, who spoke on Saturday after discussion in Seoul with Wu Dawei, China's top envoy in the talks.
But the source, as well as a Japanese official speaking in Beijing, stressed that big obstacles remained in the way of new talks, even if the secretive Kim's reported trip to China yields another vow of North Korea's willingness to sit down and discuss a dormant deal to scrap its nuclear weapons in return for aid.
"We don't want to restart six-party talks for the sake of talks," the South Korean diplomatic source said.
"North Korea should change its attitude and show seriousness in denuclearizing."
China's regional lobbying, and courting of the reclusive Kim, highlight the pressures that North Korea — isolated, poor and with a brace of primitive nuclear bombs — has brought to bear on northeast Asia, home to the world's second and third biggest economies and a big US military presence.
There have been no conclusive sightings in China of the 68-year-old Kim, who has appeared frail and gaunt since reportedly suffering a stroke in 2008. But motorcades of black cars and extensive security in Changchun, a northeast Chinese city, indicate he may be there, after entering China on Thursday.
The two neighbors do not disclose much information about Kim's travels, and only do so after he has left for home.
