Democratic presidential hopeful Bill Richardson said Wednesday that his trip to North Korea will focus on recovering the remains of U.S. soldiers, not the country's nuclear program.

The New Mexico governor is leading a bipartisan delegation that is expected to oversee the transfer of remains of U.S. soldiers killed during the Korean War. The trip on Saturday comes days before a crucial deadline in a landmark nuclear agreement the North made in February.

"If we can come back with some remains, that will be a major success of the visit," Richardson told The Associated Press while campaigning in New Hampshire. "I assume the North Koreans will raise other issues like the nuclear agreement, but I am not planning to negotiate on that."

In return for energy aid and political concessions, the North has pledged to close down and seal its main nuclear plant by April 14. It also has agreed to allow U.N. nuclear inspectors to certify the shutdown.

More than 33,000 American troops died in the Korean War from 1950-1953, and more than 8,100 are listed as missing.

"The North Koreans invited me to go and discuss the remains," Richardson said. "I contacted the White House and said look, this is important for the country, let's do this in a bipartisan way. And the White House agreed, to their credit."

Richardson, a former U.S. ambassador to the United Nations, has visited North Korea several times for talks, both in an official and unofficial capacity. Joining him for the four-day trip is Anthony Principi, the former veteran affairs secretary for President Bush.

As energy secretary in the Clinton administration, Richardson was responsible for maintaining the U.S. nuclear weapons stockpile including nuclear weapons research at weapons laboratories.

State Department spokesman Sean McCormack said Wednesday that he did not expect Richardson to raise the nuclear talks during his trip.

"That's not in his writ, if you will," McCormack said. "He's actually consulted with the State Department, as well as the White House, on this trip. The narrow focus of it is on this MIA issue and getting back the remains of these missing soldiers."

Since the breakthrough Feb. 13 nuclear agreement in Beijing, there has been little progress. The North is angry about a delayed transfer of $25 million in North Korean money frozen by Macau authorities after the U.S. blacklisted a bank in that Chinese administrative region in 2005 for allegedly helping Pyongyang launder money.

The spat, some worry, could delay implementation of the disarmament agreement.

McCormack said the United States remains optimistic that the North would meet the April 14 deadline to shut down its reactor. He acknowledged, however, that the issue of transferring the North Korean money has been more complex in its implementation than expected.