A U.S. congressman who met high-ranking North Korean officials said Tuesday he discussed the North's nuclear program and human rights issues at great length.

Rep. Tom Lantos (search), the ranking Democrat on the House International Relations Committee (search), stopped in Beijing after a three-day visit to Pyongyang.

"I had very substantive, serious discussions on a range of issues including nuclear matters, human rights matters and the economy," Lantos told reporters when he arrived in Beijing on Tuesday.

He did not give any details but said he would report to President Bush (search) about the meeting when he returned to the United States.

The North's official News Agency KCNA said Lantos held talks with Yang Hyong Sop, vice president of the Presidium of the North's Supreme People's Assembly, at the Mansudae Assembly Hall.

Lantos also met North Korean Foreign Minister Paek Nam Sun on Monday, KCNA said.

The United States, the two Koreas, China, Japan and Russia have been struggling to hold a new round of talks on the North's nuclear weapons programs. Three rounds, hosted by China, have been held since 2003, but there have been no breakthroughs.

Pyongyang said last week that it was willing to abandon its nuclear programs if Washington gives up "a hostile policy aimed at toppling our system," a spokesman of North Korea's Foreign Ministry said in a statement carried by KCNA.

Lantos, 76, was a sponsor of the North Korean Human Rights Act passed in October that allows Washington to spend up to $24 million a year in humanitarian aid for North Koreans — much of it for refugees who have fled their country. North Korea reacted angrily to the law, saying it caused "slander and insult" to Pyongyang.

Separately a bipartisan congressional delegation organized by Rep. Curt Weldon, R-Pa., also visits Pyongyang this week.