But the North Korean delegation refused to continue with negotiations until it was able to access $25m in funds that had been frozen in a Macau bank.
 
The US said on Monday that it had given approval for the funds to be released - a move that had initially raised hopes that a major sticking point had been cleared.
 
'On schedule'
 
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It is not clear what has caused the delay in transferring the funds, but Christopher Hill, the top US envoy to the negotiations, said he was optimistic that disarmament deadlines could still be met.
 
"It is our strong view that we are still on schedule," Hill said, referring to the April 14 deadline for UN inspectors to verify the closure of North Korea's main nuclear reactor at Yongbyon.
 
Kim Kye-gwan made no comment to reporters waiting at Beijing airport.
 
The six nation talks are hosted by China and bring together envoys from the US, Russia, Japan and the two Koreas.
 
The North Korean funds were frozen in 2005 following allegations from the US that they were related to North Korean money laundering and counterfeiting operations.
 
The US had expected the North Korean delegation to be satisfied with Monday's announcement that Washington had completed its investigations and would allow the funds to be moved.
 
Instead the North Korean delegation said it would not proceed with talks until the money had been transferred to the Beijing bank account.
 
Under a landmark deal agreed in February North Korea agreed to start dismantling its nuclear programme in return for promises of aid and talks on normalising relations.