Negotiations to end North Korea's nuclear programs ground to a halt Thursday in Beijing after Pyongyang's head negotiator Kim Kye-Kwan left for home.
Kim's departure ends a week of meetings in which North Korea refused to discuss detailed steps to dismantle its nuclear facilities until it received about 25 million dollars from a bank in the Chinese territory of Macau.
Chief U.S. envoy Christopher Hill Thursday expressed frustration at the delay.
"This issue of transferring the accounts has taken up a lot more time than anyone expected. So, I think we do have more work, too, and whether we get it done in the next day or two here or have to reconvene at a later date I can't tell you at this point. I hope to get some answers in that regard with the Chinese."
Hill says it is time to get on with talks on implementing a February deal where North Korea promised to close it main nuclear reactor and plutonium factory and let inspectors into the country in exchange for aid and diplomatic incentives.
The Macau authorities froze the North Korean accounts in 2005 after the U.S. accused Banco Delta Asia of helping Pyongyang launder dirty money from counterfeiting and other illegal activities.
Last week, the U.S. Treasury Department banned U.S. banks from doing business with the bank.
The nations involved then agreed North Korea could have the money back after it promised to use it for domestic aid projects.
China's Foreign Ministry spokesman Liu Jianchao Thursday says the money transfer is being held up by "technical" and "procedural" problems, but would not elaborate.