Four days of talks on the North Korean nuclear crisis ended Thursday, without a resolution to the main sticking point - how international monitors would verify Pyongyang's nuclear program.
As he was heading to the airplane to leave Beijing, U.S. envoy Christopher Hill expressed disappointment that the talks did not end with agreement on the verification issue.
Hill placed the blame squarely on North Korea, which he refers to as the DPRK, the Democratic Peoples' Republic of Korea.
"I would say there was a lot of agreement, really, among a majority of the delegations there," Hill said. "But ultimately the DPRK was not ready really to reach a verification protocol, with all the standards that are required."
The other countries in the six party grouping are China, South Korea, Japan and Russia.
Envoys said the North Koreans appeared unwilling to work with the Chinese draft on verification. No details of the proposal have been released, but delegates said it includes sections on sampling and visits to nuclear sites so monitors could verify the country's past nuclear activities.
Hill has said North Korea is not willing to put its verification commitments in writing. Pyongyang also has refused proposals to allow international inspectors to take nuclear samples out of the country.
"A number of us, especially the U.S. and Russian delegations, we have a lot of familiarity with what these things look like and what the standards should be," Hill said. "So, we tried to acquaint the DPRK with those standards and ultimately couldn't get it done during this round."
President Bush began the six party talks in 2003. Concerns over North Korea's nuclear program heightened after Pyongyang conducted an underground nuclear test in 2006.
This is likely to be the last round of such talks before President Bush leaves office in January.