James Kelly, US Assistant Secretary of State for East Asian and Pacific Affairs, made the remark during a courtesy call on Foreign Minister Yoriko Kawaguchi hours before leaving for China.

A Japanese foreign ministry official quoted Kelly as telling Kawaguchi that his working talks a day earlier provided a "good basis for talking to China and the ROK (South Korea)," about the resumption of six-nation talks including North Korea aimed at resolving the year-long crisis.

Kelly was due to arrive in Beijing later Tuesday before visiting Seoul.

Kawaguchi told the US envoy Japan wanted to cooperate closely with Washington in order to make "effective progress in solving problems at the six-way talks," according to the official.

Their meeting followed Kelly's talks with Japanese government officials Monday, including Mitoji Yabunaka, head of the ministry's Asian and Oceanian affairs bureau and Chief Cabinet Secretary Yasuo Fukuda.

As he left the meeting with the foreign minister, Kelly was asked by reporters if a date had been set for a resumption of six-nation talks.

"I don't know, I still don't know," Kelly said.

On Monday, South Korea's top presidential security aide said the second round of six-nation talks on North Korea's nuclear ambitions would probably take place December 17-18.

The US envoy arrived in Japan on Sunday as hopes for a resolution rose after the North's official Korean Central News Agency indicated Pyongyang had dropped its long-standing demand for a non-aggression treaty before it scraps its nuclear programme.

After a day of talks with Japanese officials Monday, Kelly told reporters the talks aimed at preparing for a second round of six-way talks involving the United States, China, Japan, Russia and the two Koreas were positive but inconclusive.

An inconclusive first round of six-nation talks took place in the Chinese capital Beijing in August. A second round is likely to take place by the end of the year, according to South Korean, Japanese and US officials.

The mass-selling Yomiuri Shimbun daily said Tuesday one of the options proposed by the US side is that all participants in the six-way talks sign a written promise of non-aggression on condition Pyongyang take concrete action to abandon its nuclear ambitions.

Japan agreed to it in principle but asked that the document exclude use of defensive action such as a US counter-attack on North Korea in the wake of its military strike on Japan, the Yomiuri said, citing unnamed sources.

Earlier, Kelly met separately with Shigeru Ishiba the Director General of the Defence Agency for about 30 minutes to discuss North Korea, said an agency spokesman who declined to give any more details.

The standoff with North Korea erupted in October last year when Washington said Pyongyang had admitted to running a secret uranium-enrichment programme in violation of a 1994 accord with the United States.

Just before Kelly's arrival Sunday, Pyongyang said it was ready to abandon its nuclear programme "in practice" if the United States scrapped what North Korea calls a hostile policy towards the communist country.

WAR.WIRE