Only hours after optimistic statements from the two sides and a US announcement that the discussions would be extended to Monday, both emerged from a five-hour session saying they had not yet agreed to meet again although they hoped to.
Following a morning round of talks the US Assistant Secretary of State, Robert Gallucci, had promised a 'substantive' announcement next week on the negotiations, which focus on two suspect nuclear sites in North Korea, and Pyongyang officials said they were making good progress. There was no indication of what the problem might be from either side.
Fears of the renegade Communist state have not abated in Asia, and the Japanese government continues to maintain an ambivalent position on its own nuclear non-proliferation policy.
The United States initiated a series of talks with North Korea in June after Pyongyang threatened to withdraw from the nuclear non-proliferation treaty (NPT), which would have made it a nuclear outlaw in the already tense military stand-off in East Asia. North Korea has responded positively in the talks in the hope of gaining desperately needed economic aid and diplomatic recognition.
But there is deeply held suspicion about Pyongyang's real motives, and in a kind of diplomatic 'Mutt and Jeff' strategy, the US and its two East Asian allies, Japan and South Korea, have been alternating conciliatory statements with harsh warnings to North Korea of what would happen if it persisted with its nuclear ambitions. When President Bill Clinton visited South Korea last weekend, he said that if North Korea were to develop and use a nuclear weapon 'it would mean the end of their country as they know it. We would overwhelmingly retaliate.'
Japan has repeatedly said it will not make its own nuclear weapons. But during last week's G7 summit in Tokyo the Japanese delegation refused to endorse an indefinite extension of the NPT, which expires in two years' time. The government says this is because there is still no national consensus on prolonging the treaty, but Japan's neighbours suspect Tokyo of effectively reserving the nuclear option in the face of the North Korean threat.
Japan has watched the development of North Korea's nuclear programme nervously, and was particularly shocked when at the end of May North Korea test-fired the Rodong 1, a long- range missile which could reach large parts of the Japanese archipelago. On Wednesday Japan's Foreign Minister, Kabun Muto, said the North Korean leader, Kim Il Sung, was 'crazy'.
No one has suggested that Japan possesses nuclear weapons. But with its technological expertise and stockpiles of plutonium shipped in from Europe for power plants, the country is in a position to go nuclear in a very short time.
Meanwhile, a congressional committee in Washington has warned that North Korea may be preparing for military confrontation as a way out of its current economic and political isolation. According to the House of Representatives Republican Task Force on Terrorism, Pyongyang is demanding that the West rescue its failing economy, or it will 'strike out against South Korea and/or Japan, shattering the stability of the entire Pacific Rim'.
Since March North Korea has been refusing inspectors from the International Atomic Energy Agency (IAEA) access to two buildings inside a nuclear research compound. Scientists from the IAEA believe the buildings may contain evidence that Pyongyang is stockpiling plutonium, a critical ingredient in nuclear bombs.