The six-nation agreement unveiled by China on Wednesday was hailed by President George W. Bush as a commitment "to realize a Korean Peninsula that is free of nuclear weapons" and to "help secure the future peace and prosperity of the Northeast Asian region."

The United States will lead and fund the program as Pyongyang makes a full declaration of its nuclear assets by a December 31 deadline set in the agreement, officials said.

Hill said Thursday a US team would be go to North Korea next week to begin the process, beginning at the key Yongbyon nuclear complex, the source of bomb-grade plutonium for Pyongyang which conducted its first nuclear test a year ago.

"We hope that we can get them in early next week and they can begin the actual task of disablement," he told reporters.

"Our hope is that as we get to the end of this year, we will have (not) only shut down but also disabled (their nuclear program), such that if the North Koreans ever wanted to change their mind, it would be quite difficult to restart the program," he said.

The agreement, reached between China, the United States, the two Koreas, Russia and Japan, is the second phase of a long-running process aimed at ending North Korea's nuclear weapons drive.

North Korea committed to provide "a complete and correct declaration of all its nuclear programs, nuclear weapons programs, materials, and any proliferation activity," Bush said in a statement.

It "also committed not to transfer nuclear materials, technology, or know-how beyond its borders," said Bush, who is working hard to ensure that his administration's hardline policy on North Korea succeeds.

Hill told the PBS television News Hour program Thursday that the next phase is key to ensuring that Pyongyang does not go back on its word.

"We've gotten them shut down but, frankly, they could kick out the (UN) inspectors, take the seals off and turn them back on. So the idea of disabling is to make it difficult to turn (the facilities) back on."

He said the US team would stay at the Yongbyon complex to oversee the process and try to recover an estimated 50 kilograms (110 pounds) of plutonium already produced.

It would also seek complete information on other possible North Korean nuclear sites.

"A key factor in all of this is to make sure that as we shut down Yongbyon ... we don't want a situation where they have some other facility where they're producing bomb-making material by another means," Hill said, apparently referring to the possibility of a uranium based program.

Hill said disabling of North Korea's nuclear programs and materials could move the country closer to normal relations with the United States.

"Ultimately this is all part of a process of normalizing our relationship with North Korea. Now, we're doing this on a step-by- step basis ... we have made it very clear that we're not going to normalize with North Korea until they get out of the nuclear business."

He said Washington was also not yet ready to remove Pyongyang from a list of state sponsors or terrorism, despite its request to do so, because of outstanding issues including Japan's concerns over the North's kidnapping of Japanese citizens nearly three decades ago.

"It's a sensitive issue (for the Japanese) ... they would like to see some progress on that issue in connection with taking North Korea off the terrorism list.

"We've had to work this issue very carefully ... our hope is that we can, indeed, get them off this list."