Negotiators to talks on ending North Korea's nuclear ambitions have arrived in Beijing to work out the next steps in the process. As Daniel Schearf reports from Beijing, the talks are entering a tricky stage of trying to verify all of North Korea's nuclear facilities and materials and set a timetable for dismantling them.

US envoy Christopher Hill, right, talks to reporters after lunch meeting in Beijing, 17 Jul 2007

The six-nation talks are expected to take on new momentum now that international nuclear inspectors have confirmed that North Korea has shut down its Yongbyon nuclear reactor.

This week, delegates from North Korea, the United States, Russia, South Korea, Japan and China will discuss the next steps in ending Pyongyang's nuclear weapons programs - identifying all of its nuclear facilities and dismantling them.

Before leaving Pyongyang Tuesday, the North's head negotiator, Kim Kye Kwan said detailed progress needs to be made at the Beijing talks.

"There should be discussion on how to define the targets of the second phase, the obligations for each party, and also the sequence of the actions," he said.

Some analysts have said those steps may be harder to accomplish than the shutdown of the reactor, because North Korea will be required to reveal details of its secret efforts to build nuclear weapons.

Pyongyang promised in February to dismantle its nuclear programs in return for aid and an end to its diplomatic isolation. The first step - shutting down the reactor - took months longer than expected because of a financial dispute that only was resolved last month.

Once the facilities are dismantled, foreign ministers from all six nations will meet for the first time.

On arriving in Beijing Tuesday, the chief U.S. negotiator, Assistant Secretary of State Christopher Hill, told reporters there is a lot of work to do. He indicated talks are on track for the foreign ministers' meeting to take place, but exactly when would have to be discussed,

"We will have a ministerial. But, we've got to work on the timing and then work out exactly what we are going to do with that." Hill said.

The effort to end North Korea's nuclear ambitions began in 2002 after the U.S. accused Pyongyang of trying to make bombs out of enriched uranium, in violation of international pledges the North had made to not build nuclear weapons. Pyongyang has never publicly admitted having such a program, but says it has nuclear weapons. Last year, North Korea tested its first nuclear explosive device.