North Korea (search) offered on Tuesday to freeze its nuclear program, including weapons and energy development. Secretary of State Colin Powell (search) called the offer "positive" as a U.S. delegation traveled to the isolated communist nation, possibly to tour a disputed nuclear plant.

The moves came as the United States, China, Russia, Japan and the two Koreas scrambled to arrange a new round of negotiations on Pyongyang's nuclear weapons program, with South Korea and Russia saying they are unlikely this month.

North Korea has said before it is willing to freeze its "nuclear activities" in exchange for U.S. aid and being removed from Washington's list of terrorism-sponsoring nations.

On Tuesday, it specified it would not test or produce nuclear weapons and even stop operating its nuclear power industry "as first-phase measures of the package solution."

In a commentary carried by the official KCNA news agency, North Korea called the offer "one more bold concession" aimed at resolving the international standoff.

Powell said in Washington, "It was an interesting statement. It was a positive statement. They, in effect, said they won't test, and they implied that they would give up all aspects of their nuclear program, not just weapons program."

He said he hoped the North Korean proposal "will allow us to move more rapidly toward six-party framework talks."

The Bush administration has said it wants evidence that North Korea is beginning to dismantle its nuclear weapons programs before it delivers any concessions.

Meanwhile, the unofficial delegation of Americans, which included a former government official, a nuclear expert and a retired academic, flew from Beijing to North Korea, possibly to tour the communist country's disputed nuclear plant at Yongbyon.

"It's a very private visit. We're not representing the U.S. government or anyone else," said Jack Pritchard, once a member of former President George H. W. Bush's National Security Council staff and a one-time State Department official.

Members of the group refused comment on reports they might visit the Yongbyon complex.

A South Korean Foreign Ministry official said on condition of anonymity they were to stay in the North from Tuesday to Saturday. Another pair of Americans, both congressional staffers, also were scheduled to visit Pyongyang this week.

The Yongbyon complex is at the heart of the standoff, and there has been no outside access to the facility since North Korea expelled U.N. nuclear inspectors at the end of 2002.

On Tuesday, North Korea said its first-step proposal should be the focus of preparations for new talks.

"If the United States keeps ignoring our efforts and continues to pressurize the DPRK to scrap its nuclear weapons program first while shelving the issue of making a switchover in its policy toward the DPRK, the basis of dialogue will be demolished and a shadow will be cast over the prospects of talks," KCNA said.

DPRK stands for Democratic People's Republic of Korea, North Korea's official name.

Powell said he is convinced that the six nations that participated in talks last year -- the two Koreas, the United States, Russia, China and Japan -- want to hold another round.

South Korea's Unification Ministry (search), which handles affairs with North Korea, says North Korea has at least three nuclear reactors.

Last year, it restarted a five-megawatt reactor at Yongbyon. An unfinished 50-megawatt reactor also stands at Yongbyon, and a 200-megawatt one is located just northeast of the site at Taechon.

A U.S.-led international consortium had been building two 1,000-megawatt light-water reactors on the country's east coast. But that project was suspended last month amid the nuclear standoff.

North Korea's neighbors agreed to help build the light-water reactors because they are more difficult to convert to weapons use. North Korea's offer to suspend all nuclear activities, even those for peaceful purposes, could be aimed at easing their suspicions.

Traveling to North Korea with Pritchard were Sig Hecker, a nuclear specialist at the Los Alamos National Laboratory in New Mexico, and John W. Lewis, professor emeritus of international relations at Stanford University.