Secretary of State Colin Powell told Congress Thursday that North Korea had turned down a proposal by the Bush administration to involve China and other nations in talks with the United States over North Korea's nuclear weapons programs.

Powell said the United States had told Pyonyang that Asian neighbors have a stake in putting the "nuclear genie back in the bottle," and corking it.

"We have here a regional situation," Powell said. "It can't be just the United States," trying to reduce the threat from North Korean weapons development.

In reply, North Korea insisted on direct talks with the United States alone, Powell told the House Budget Committee.

Also Thursday, Defense Secretary Donald H. Rumsfeld said North Korea may pose a bigger threat as a supplier of nuclear weapons than it would as a potential aggressor in Asia.

"They sell almost everything," Rumsfeld told the Senate Armed Services Committee. "They are the world's greatest proliferator of missile technology," and hence a problem for more than one nation to solve, he said.

At the United Nations, the United States said Thursday that U.N. sanctions to punish North Korea for its nuclear program are not an option for now. U.S. Deputy Ambassador Richard Williamson said the Bush administration wants to pursue a diplomatic solution.

The United States and North Korea agreed in 1994 to freeze North Korea's plutonium program in exchange for energy supplies. It turned out North Korea went ahead with a separate program to develop enriched uranium, Powell noted Thursday.

Since then, North Korea has confirmed having an active nuclear program and said it would quit an international treaty designed to limit the spread of nuclear weapons technology.

Rep. Dennis Moore, D-Kan., questioned the administration approach, and said the United States should begin negotiations with North Korea directly. Asian neighbors could be brought in later, Moore said.

White House spokeswoman Claire Buchan, speaking earlier Thursday, reiterated that Bush will not negotiate alone.

"Our position remains the same, that this is a multilateral issue that needs to be" handled by multiple nations, she said.

On Wednesday, the Bush administration said it is concerned that its goal of a denuclearized North Korea may not be possible unless China uses diplomatic leverage to force a retreat by Pyongyang.

China accounts for 80 percent of the foreign assistance North Korea receives, Powell said then.

China's U.N. Ambassador Wang Yingfan said Wednesday: "We have to handle this. That's our responsibility. But how to, and when, I think we need some consultation" among members of the U.N. Security Council.

Since North Korea's uranium-based nuclear program was first disclosed last October, China has made clear that it opposes the existence of nuclear weapons on the peninsula.

U.S. intelligence officials, meanwhile, said Wednesday that Pyongyang has an untested ballistic missile capable of hitting the western United States and possibly targets farther inland.

The North Korean weapon is a three-stage version of its Taepo Dong 2 missile, Vice Adm. Lowell Jacoby, director of the Defense Intelligence Agency, told reporters. CIA Director George Tenet, who joined Jacoby before the Senate Armed Services Committee, acknowledged that North Korea has a missile that can at least reach the West Coast.

However, U.S. intelligence officials said later North Korea has demonstrated no new missile capabilities in the last year. The officials, speaking on the condition of anonymity, said the statements were based on the same information that led U.S. intelligence to conclude a few years ago that North Korea was close to being able to flight-test a three-stage Taepo Dong 2.

Without flight-testing, the reliability of such a missile is questionable. For several years, North Korea has held to a voluntary moratorium on flight tests of its long-range missiles, although American officials say Pyongyang may renew them at any time.

John Bolton, undersecretary of state for arms control, said in an interview the United States believes China could play a major role in influencing North Korea but that Beijing insists its leverage is minimal.

"We don't see any way in which we can get the North Koreans to move without China's help," Bolton said.

The head of North Korea's diplomatic representation in Germany, Pak Hyon Bo, told the German daily Financial Times Deutschland on Wednesday that his country will not respect any resolutions or suggestions by the Security Council.

"We are no longer a member of the Non-Proliferation treaty," Pak said.

Pyongyang sees its nuclear programs essentially as a bilateral issue with the United States and has said the two sides should deal with it in discussions leading to a nonaggression treaty. The Bush administration has shown no interest in a bilateral approach.