He said that in order for there to be a peaceful solution of the standoff, North Korea must go back to the negotiating table and continue the process that began in April.

As far as China was concerned, the format for the talks, whether multilateral as insisted by the US, or bilateral as demanded by the North, was less important than substantive progress towards ending the standoff, he said.

Mr Dai's visit came hot on the heels of his trip to Moscow and closely followed a visit to the US by Wang Yi, another deputy foreign minister. The shuttle diplomacy demonstrated China's desire to bring all sides back to the table, Mr Kong said.

Analysts said time was running short. On Sunday, North Korean diplomats were reported to have told US officials the country had finished reprocessing 8,000 spent nuclear fuel rods into weapons-grade plutonium.

After talks in Beijing involving the US broke down in April, North Korea, apparently dissatisfied with what it perceived as inadequate support from China, sought Russian help to break the impasse.

The appointment of the influential Mr Dai signified a shift to a more proactive Chinese policy on the Korean peninsula. The move was in line with the more assertive foreign policy demonstrated when Mr Hu went to the G8 meeting in Evian, France, said Li Dunqiu, a Korean expert at the Chinese Academy of Social Sciences.

China has considerable leverage over North Korea, as its biggest aid donor. But the increasingly close ties between South Korea and China have rattled the North.

While South Korean President Roh Moo-hyun visited Beijing last week, China also sought to mend frayed ties with the North by rebuilding the border bridge over the Yalu river and improving conditions for sheltering North Korean illegal immigrants before repatriating them, Mr Li said.