The United States, which will join the talks expected to take place in Beijing, wants to hold them in August ahead of a UN general assembly meeting in New York in September, Japan's top-selling daily Yomiuri Shimbun said in a dispatch from Washington, quoting government sources.

Apart from China, North Korea and the United States, the six-way talks will include officials from Japan, South Korea and Russia.

The Yomiuri said North Korea has been contacting participating nations directly without consulting China, Pyongyang's closest ally.

A rift between China and North Korea became apparent after the three-way nuclear talks held in April in the Chinese capital involving Beijing, Pyongyang and Washington, the daily said.

North Korea has grown frustrated with China, which sided with the US position by demanding the Stalinist regime give up its nuclear weapons while acting as a mediator between Pyongyang and Washington, it said.

The nuclear crisis erupted in October when Washington accused the Stalinist state of reneging on a 1994 bilateral nuclear freeze accord by setting up a clandestine nuclear program based on enriched uranium.

North Korea then kicked out International Atomic Energy Agencymonitors and withdrew from the nuclear non-proliferation treaty.

Pyongyang has since claimed to have reprocessed 8,000 spent nuclear fuel rods at its nuclear plant at Yongbyon.

Washington believes North Korea had extracted enough weapons-grade plutonium for about two nuclear bombs before it froze its Yongbyon plant. Reprocessing the fuel rods could provide enough additional material for around six bombs within months, according to analysts.

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