Officials in Washington said the talks, scheduled to start on 27 August in Beijing, would likely be the start of what would prove a long process.

Chinese Foreign Minister Li Zhaoxing, on the other hand, struck an upbeat note, saying that the talks “provide a significant opportunity for the nuclear issue on the Korean peninsula to be resolved by dialogue in a peaceful way.”

The US said in October that North Korea had admitted to running a clandestine programme to enrich uranium and build a nuclear arsenal.

Since then, the isolated communist nation had evicted United Nations nuclear inspectors, restarted its nuclear reactor and bowed out of the nuclear Non-Proliferation Treaty.

Though North Korea claims to have at least one or two atomic weapons, it is unlikely that it has the capability to mount them on a missile.

Regional concern

Still, concern remains that the country could threaten neighbouring Japan or South Korea, where about 37,000 US troops are based, and destabilise Northeast Asia.

In the latest of numerous North Korean attacks on the US, the Committee for the Peaceful Reunification of the Fatherland berated joint US-South Korean war games as provocation.

“If the US takes the road of war against the North behind the curtain of dialogue, not withdrawing its hostile policy, we will never give up the nuclear deterrent," a statement on the official KCNA news agency said.

North Korea is trying to develop an inter-continental ballistic missile capable of reaching any target in North America.

The Taepodong-2 missile has a current range estimated at between 3500 and 6000 km, putting Hawaii and Alaska within reach.
 
Still, reducing the size of a nuclear warhead for a missile is a complex task and requires specific materials such as Tritum which it could ill afford, analysts said.