(AP Photo/Frederic J. Brown, Pool)
The six-nation talks, which reopen today in the Chinese capital, have been plagued by delays and discord since they began in August 2003.
The United States has sought to line up support against Pyongyang's nuclear ambitions by enlisting its neighbors -- including China, Japan, Russia and South Korea -- in the discussions.
The North exploited divisions among the United States and its partners in an effort to change the subject and buy time to develop its atomic arsenal.
But North Korea's Oct. 9 nuclear test of a low-yield nuclear device seemed to stiffen the will of other countries -- particularly China -- to persuade it to disarm.
Beijing joined a unanimous U.N. Security Council resolution sanctioning North Korea for its nuclear test, and brought Pyongyang and Washington together just a few weeks later to agree to resume nuclear discussions.
North Korea had boycotted the talks and called for the United States to stop blacklisting a Macau bank where the regime held accounts. Washington accused North Korea of using the bank in a scheme to launder money and print counterfeit U.S. currency.
The U.S. insists its accusations against the bank are a separate legal matter, but Washington has agreed to conduct working-level talks about the topic alongside the nuclear negotiations.
Assistant Secretary of State Christopher Hill, the U.S. nuclear envoy, says the main task now is to implement an agreement from September 2005 -- the only accord negotiators have reached so far -- when the North promised to abandon its nuclear program in exchange for security guarantees and aid. The alternative, he says, is sanctions.
"I hope that (North Korea) understands that, as the rest of us do, that we really are reaching a fork in the road," Hill said after arriving in Beijing.
Kim Kye Gwan, North Korea's chief negotiator, said Saturday that it is up to the Americans to take the first step. After arriving in Beijing, he called the lifting of the U.S. financial restrictions a "precondition" to further negotiations.
Hill, meanwhile, emphasized that U.N. sanctions imposed after the North's nuclear test would remain in effect until the North's gives up its atomic programs.
"Most of the world has told them that we don't accept them as a nuclear state," he said. "If they want a future with us, if they want to work with us, if they want to be a member of the international community, they're going to have to get out of this nuclear business."
Former Secretary of State Colin Powell told CBS' "Face the Nation" Sunday that "I don't yet see the conditions for a breakthrough" in the diplomatic impasse over North Korea's nuclear program. But he said that a political solution can eventually be found.
All the chief delegates met for dinner Sunday, but Hill said he merely exchanged pleasantries with North Korea's Kim. He said that the North did not want bilateral talks with any delegation before Monday's official start.
There is no scheduled date for the negotiations to end, but Hill said he hoped to return to Washington by the end of the week.
The latest North Korean nuclear crisis began in late 2002, when U.S. officials said the North admitted running a secret nuclear program. The program violated a 1994 deal with the U.S., in which North Korea agreed to halt its atomic development.
After its admission, North Korea withdrew from the Nuclear Nonproliferation Treaty, expelled international inspectors and restarted its main nuclear reactor in order to make plutonium for bombs.