North Korean nuclear disarmament talks collapsed here yesterday after failing to reach agreement on how to determine if the secretive nation had told the truth about its atomic programmes.

Chief US envoy Christopher Hill departed Beijing after four days of talks blaming the communist regime for refusing to agree on a protocol to verify a historic declaration it made in June this year about its nuclear activities.

"Ultimately, the DPRK (North Korea) was not ready, really, to reach a verification protocol with all the standards that are required," Hill told reporters as he prepared to leave Beijing.

With no date set for more talks, this week's failure all but dashed the hopes of US President George W. Bush's administration to make progress on North Korean disarmament before Barack Obama moves into the White House.

The Bush administration had made solving the North Korean nuclear impasse a key foreign policy priority.

Hill admitted that the goal this week of securing a venfi-cation deal had always been an extremely hard task.

'We had some very ambi-

tious plans for this round. Unfortunately we were not able to complete some of what we wanted to do," Hill, an assistant secretary of state, said at Beijing's airport.

"We worked very hard on verification but ultimately we were not able to get an agreed verification protocol."

One key sticking point has been North Korea's refusal to allow samples of atomic material to be taken away, envoys to the talks had said earlier in the week.

Under a landmark six-nation deal reached in February 2007, North Korea agreed to give up the nuclear programmes it had spent decades developing.

That pact also called for the other nations involved in the talks to deliver one million tonnes of fuel oil or energy aid of equivalent value to the North.

However the negotiations, which began in 2003, have been mired in countless setbacks. and did not prevent Pyongyang from testing its first atomic bomb in 2006.

And although the North made its declaration of its atomic activities in June, the next crucial step in the process was working out a way to determine if it had been telling the truth.