Negotiators in six-nation talks to halt North Korea's nuclear drive gathered close to its border on Thursday for two days of discussions seen as important to keeping disarmament on track.
The talks in Shenyang, a vast industrial city in northeast China, are aimed at paving the way for agreement on a sequence of events for North Korea to declare and eventually disable all of its nuclear weapons programmes.
It is the second key phase of a six-nation accord signed in February under which the North, one of the world's most impoverished countries, agreed to end those programmes in exchange for fuel aid, security guarantees and diplomatic concessions.
"We're looking forward to a very good, a very substantive discussion of some technical issues," US chief negotiator Christopher Hill told reporters in Shenyang, about 200 kilometres (120 miles) from the border.
"Obviously technical issues are very important issues."
The talks are considered vital to enabling further progress in the next round of full six-nation disarmament meetings in Beijing, tentatively set for early September.
"When we sit down and actually do the sequencing and the timeframe, that's something we will do in the plenary," Hill said on Thursday.
"What we are trying is to make sure we have a common understanding of the technical tasks, so that when we sit down in the plenary, we won't be talking about things for the first time."
The negotiations group North and South Korea, China, Japan, Russia and the United States.
North Korea honoured its initial commitments last month by closing its main nuclear reactor at Yongbyon and opening its doors to UN International Atomic Energy Agency inspectors.
In remarks to reporters on Wednesday and Thursday, Hill repeatedly emphasised the need for a "declaration," meaning a complete North Korean list of its nuclear arms-related activities.
Hill insisted earlier this week that the reclusive communist nation must come clean on all of its nuclear weapons programmes for the overall process to move forward.
The United States suspects the North, which conducted its first atomic weapons test last October, of running a secretive highly enriched uranium programme in addition to the projects it has already admitted to.
"I think the uranium enrichment process needs to be addressed in the context of the declaration of programmes and I think we have an ongoing effort to do that. I can't be more specific at this time," Hill said.
Prior to the actual working group discussions, the negotiators spent the first part of Thursday mostly in bilateral sessions.
Hill met with the Japanese delegation before scheduled talks with the Russian group, but said he had no plans for a bilateral encounter with the North Korean team.
"We talked about how to carry the discussions forward in a balanced manner," Japanese chief negotiator Kenichiro Sasae said of his morning encounter with Hill.
The talks take place amid a domestic crisis for North Korea which has been hit by devastating floods that have affected up to 300,000 people, according to the World Food Programme.
"It's a serious humanitarian issue, and we would like to be a part of the effort to assist. So we need evaluate the situation and see what we can do to help," Hill said.