Seoul, South Korea ? North Korea pledged to detail its nuclear programs and disable all activities at its main reactor complex by year’s end, then signed a wide-ranging reconciliation pact with South Korea today promising to work for peace on the divided peninsula.

North and South Korea pledged to seek a permanent peace agreement replacing the 54-year-old cease-fire that ended the Korean War. The pledge came a day after the North made its firmest commitment yet to nuclear disarmament.

North Korean leader Kim Jong Il and South Korean President Roh Moo-hyun also promised to boost economic ties – opening regular cargo railway service along restored tracks crossing their heavily armed border and creating a joint fishing zone on their disputed sea frontier.

The two leaders signed the wide-ranging agreement promising cooperation for peace after three days of summit meetings in Pyongyang, the second such meeting between the countries.

Under a separate multination agreement reached in February, Pyongyang was required to shut down and seal its sole operating reactor at its main nuclear complex, which it did in July after the U.S. reversed its hard-line policy against the regime. The second phase required it to disable the reactor and provide a full description of all its nuclear programs. Wednesday’s agreement at talks in China called for that to happen by the end of the year.

The North said it would allow the U.S. to lead a group of experts to Pyongyang within two weeks “to prepare for disablement” of its nuclear facilities, Chinese Vice Foreign Minister Wu Dawei said in Beijing. The U.S. wants the dismantling process to be so thorough that a nuclear facility could not be made operational for at least 12 months.

President Bush hailed the nuclear deal and said it reflected the “common commitment” of the talks to shut down North Korea’s atomic weapons program.

The U.S. has agreed to lead disablement activities and provide the initial funding for them. Washington also reiterated its willingness to remove North Korea from a list of countries that sponsor terrorism, a key demand of Pyongyang.

No timetable was set for this action, but a joint statement said it will happen “in parallel with” the North Korean government following through on its commitment.

“The two sides will increase bilateral exchanges and enhance mutual trust,” the statement says.

Besides the U.S. and China, three other countries – Russia, South Korea and Japan – participated in the talks with the North.

The five countries reiterated a commitment to deliver aid under the February disarmament deal granting the North the equivalent of 1 million tons of fuel oil. On Friday, in anticipation of the agreement, the U.S. announced it would spend up to $25 million to pay for 50,000 tons of heavy fuel oil for North Korea.