Pyongyang is still insisting that Washington lift financial measures against North Korean interests before Pyongyang will move ahead on the issue of dismantling its nuclear weapons program.

U.S. Treasury official Daniel Glaser, who met with North Korean financial officials on the sidelines of the nuclear talks earlier this week, says those talks were "businesslike and useful." But Glaser says further talks are needed before there can be any agreement between the two sides.

"We hope to get to do that. We've discussed the possibility of meeting next month, perhaps in New York," he said.

The dispute revolves around a bank in Macau, Banco Delta Asia, which Washington says helped North Korea with counterfeiting and money-laundering activities. U.S. restrictions on the bank have resulted in a North Korean account there with $24 million being frozen.

Thursday, amid cautious expressions of optimism, it was announced that the nuclear talks among North and South Korea, the U.S., China, Japan and Russia would be extended by a day until Friday.