A top U.S. envoy warned Tuesday that time was running out in negotiations as he held a new round of talks with his North Korean counterpart to resolve a deadlock over the communist nation's nuclear program.

Still, neither side expected to reach a conclusive deal during the daylong talks at the U.S. Embassy in Singapore.

"We are not looking for an agreement," Assistant Secretary of State Christopher Hill, the top U.S. nuclear negotiator, told reporters before starting talks with North Korean Vice Foreign Minister Kim Kye Gwan.

"I think we are looking to have a consultation on some of the issues that have kept us apart for several months and certainly I will be discussing the fact that we are kind of running out of time," Hill said.

The talks ended after about eight hours but no details of the outcome were immediately released. Hill was scheduled to speak to reporters later Tuesday.

Six-nation talks on disarming Pyongyang of its capabilities to build nuclear weapons have been stalled for months because of a disagreement over disclosure. Hill had said Monday that the two sides cannot "afford any further delays here."

The United States says North Korea missed a Dec. 31 deadline to provide a full inventory of its nuclear activities and facilities. North Korea says it provided a list in November, but the U.S. says it was incomplete.

Japan's Kyodo news agency quoted Kim as saying the U.S. caused the deadlock. Kim said he was not optimistic about Tuesday's talks "because we do not yet completely understand the U.S. position," according to Kyodo.

Hill disagreed with the reported comment.

"They know precisely what the issues are and they understand that we didn't want to meet unless we can achieve something," he said Tuesday.

The main sticking points are believed to be what Pyongyang will reveal about nuclear know-how or materials it may have provided to other nations, and allegations about a secret North Korean uranium enrichment program in addition to its known plutonium program.

North Korea began disabling its main nuclear facilities last year in exchange for aid and diplomatic concessions under an agreement with China, Japan, Russia, South Korea and the United States, the other countries involved in the six-party talks.

Most of the tasks to disable the facilities have been completed, with American experts working to ensure the plutonium-making facility would require at least a year to become operational again.

From Singapore, Hill will go to Beijing, where he will meet with the heads of delegations of South Korea, Japan and China. He said he will also brief the Russian ambassador to China.

Hill said there is also a possibility of a meeting between South Korea, Japan and the U.S. but that no date had been set.