North Korea's nominal number two leader said dialogue with foreign powers was impossible without respect for the sovereignty of the communist state.

China has sought to defuse international confrontation over North Korea by hosting six-party talks since August 2003.

The irregular negotiations bring together North and South Korea, China, the United States, Japan and Russia, seeking to end the North's nuclear weapons ambitions in return for aid.

"For us there can be no dialogue, nor any negotiations where the principles of respect for sovereign rights and equality are denied," Kim Yong-nam told delegates at the Non-Aligned Movement summit in the Egyptian resort town of Sharm el-Sheikh.

Kim, the president of North Korea's People's Assembly, said the talks ended because most of the involved parties had abandoned these principles.

"In light of the prevailing situation, the government of the DPR Korea had no other way but to take decisive measures to further strengthen its nuclear deterrence," he said.

Washington has for years being trying to press Pyongyang to end its atomic ambitions and reign in missiles that threaten US allies South Korea and Japan.

North Korea launched a number of missiles earlier this month, an act of defiance to the United States on its independence day that further stoked regional tensions.

• UN, US move to increase pressure on N. Korea