Six-nation talks on North Korea's nuclear program ended Saturday without any major breakthrough, but a U.S. official declared them "very successful" and participants promised to push ahead with diplomatic efforts. The North denounced the United States, saying it wasn't willing to reach a settlement.

The United States, North Korea and other governments agreed to hold more senior-level talks before July and form a lower-level working group to handle details of solving the 16-month-old dispute, officials announced.

The governments failed to agree on the U.S. demand that Pyongyang abandon its nuclear program entirely, said the chief Chinese delegate, Wang Yi, who cited an "extreme lack of trust." He said the North said Washington must first give up what Pyongyang (search) calls a "hostile policy" toward the isolated, communist regime.

The North's delegate, Vice Foreign Minister Kim Kye Gwan (search), said he saw no "positive result" from the four-day meeting, the second round of six-nation talks organized by China. A first round in August produced no substantive results.

"The U.S. delegation did not have an attitude to resolve the nuclear issue through peaceful negotiations," Kim said at a news conference.

The talks ended on a discordant note when the governments failed to issue a planned joint statement after they couldn't agree on North Korea's last-minute request to change its wording. Pyongyang wanted the statement to refer to "differences" among delegates.

Still, a U.S. official said the atmosphere of two one-on-one meetings between the American and North Korean delegations had gone better than he expected, but cautioned many details remained to be worked out.

Other participants in the talks were South Korea, Japan and Russia. South Korea said it was "satisfied" with the talks. Russia, in a statement from Moscow, said the talks were "useful."

Washington repeatedly has demanded the comprehensive dismantling of the North's nuclear program, refusing to grant concessions if Pyongyang freezes the program but does not abolish it. The North says it won't give up nuclear activities that aren't related to weapons.

"The parties did not have consensus on this proposal or the scope of North Korea's giving up nuclear weapons," said Wang, the Chinese delegate and a vice foreign minister.

However, he said, North Korea "made clear its readiness" to give up its weapons program "once the United States gives up its so-called `hostile policy' toward North Korea."

The United States affirmed that had "no hostile intent" against the North. "It has no intention to invade or attack North Korea," Wang said. "It has no intention to seek regime change."

The governments established what they called a framework to continue diplomatic work. Even before the talks started Wednesday, China warned that the dispute couldn't be solved in a single round of meetings.

After conflict foiled the planned joint statement, China issued what it called a closing "chairman's statement." Wang, who read it out at a news conference, appealed to reporters not to dwell on disagreements.

"There are plenty of them, which is an objective fact," he said. "I suggest you pay more attention to the positive."

Nevertheless, he acknowledged, "The main reason for these differences is the extreme lack of trust."

North Korea and the United States have been at odds over Pyongyang's nuclear ambitions for years and especially since October 2002, when U.S. Assistant Secretary of State James Kelly said the North told him it had a secret program based on enriched uranium (search) — thus, Washington said, violating a 1994 agreement.

Kelly led the U.S. delegation in meetings this week.

North Korea denies having a uranium program besides its known plutonium-based program, but it brandishes the threat of what it describes as its "nuclear deterrent" in an effort to extract concessions.

U.S. officials believe North Korea already has one or two nuclear bombs and could make several more within months. The North's five negotiating partners all say they want the Korean Peninsula to be nuclear-free. South Korea, China and Russia offered the North crucial energy aid if it agreed to disarm.