"I think the deal violates the principle that President Bush followed during his first term in office that we don't reward bad behavior, especially by rogue states and proliferators like North Korea," Bolton said.

Bolton's criticism of the six-party deal underscores his discontent with the Bush administration's North Korea policy, which has softened since hardliners like Bolton and former Defense Secretary Donald Rumsfeld left following the Republican Party's humiliating setback in November's midterm congressional elections.

Bush responded to similar comments Bolton made to CNN's Wolf Blitzer shortly after the agreement was reached Feb. 13, saying at a news conference, "I strongly disagree with his assessment."

The six countries discussing the North Korean nuclear program -- North and South Korea, the United States, China, Japan and Russia -- agreed in Beijing that Pyongyang will receive various forms of aid, including 50,000 tons of heavy fuel oil up front, in return for taking steps toward nuclear disarmament.

More important than the reward of heavy fuel oil, Bolton said, is that the deal alleviated the international diplomatic pressure Washington had built up after North Korea's missile tests in July and its nuclear test in October provoked two U.N. Security Council resolutions sanctioning Pyongyang.

"My concern is that we had North Korea in a corner after the nuclear test and now we've helped them get out of the corner," he said, pointing to the resumption of talks between the two Koreas, the probability that Seoul will resume the flow of aid to Pyongyang stopped after the nuclear test and reports that Australia will resume diplomatic ties with the North Koreans.

Bolton, the assistant secretary for international security and nonproliferation at the State Department before his stint as U.N. ambassador, said North Korea will not give up its nuclear program voluntarily and will inevitably cheat on the agreement.

"My hope is that if North Korea does what it normally does -- that is to say, cheat or violate the deal or overreach -- that still provides the United States and Japan and others with an opportunity to repudiate the deal," he said.

"Because North Korea is not going to give up its nuclear weapons program voluntarily," he continued. "It will negotiate about that, it will agree to things related to it in hope of getting tangible economic and political benefits, but it's not going to give them up and I think that's clear now."

Instead, according to Bolton, the United States should "increase North Korea's isolation, strengthen the Proliferation Security Initiative, deny them hard currency, technology, materials for weapons of mass destruction."

The Proliferation Security Initiative, established in 2003, is a voluntary group of over 70 countries working to halt the trafficking of weapons of mass destruction, their delivery systems and related materials to and from places that raise proliferation concerns.

"Ultimately you have to look for the reunification of the Korean Peninsula," Bolton said, but he stopped short of advocating forceful regime change. "It's only a question of time, I think, anyway, when that regime will collapse."

"This regime is more fragile than people think because it's a dictatorship that rests on a very small base," he added.

On another issue, Bolton expressed strong support for Japan's bid for a permanent seat on the U.N. Security Council, but said Tokyo's campaign strategy was flawed.

"I've always been a supporter of Japan becoming a permanent member and that's what we tried to persuade the government of Japan that the so- called G-4 approach was not going to work," Bolton said.

The G-4 or Group of Four -- Japan, Brazil, Germany and India -- failed in July 2005 to garner the support necessary to enlarge the council by increasing the number of permanent and nonpermanent seats.

Bolton said he favors a "Japan First" approach in which "you bring Japan on as a permanent member and then make decisions about other countries later."

"Japan already has the best case for permanent membership and the most support," he said, citing Japan's global economic reach and contribution to U.N. peacekeeping missions.

"The trouble with the G-4 approach is that it didn't bring any additional support to Japan," Bolton said. Instead, "actually what happened was you united all of the opponents of the four," he said.

"Japan doesn't have any problem with the other four permanent members. It has a problem with China. So you have to recognize what the problem is and go to work on it diplomatically," he added.

In the end, however, China's opposition to Japan may be intractable, Bolton said. "It may be that there's no strategy that will prevail. But since everything else has failed, I don't see what you have to lose."