A UN nuclear watchdog team prepared to leave for North Korea on Tuesday to negotiate terms for inspectors to confirm the shutdown of Pyongyang's nuclear reactor and source of bomb-grade plutonium.
Pyongyang recently agreed to implement a nuclear disarmament deal struck in February, reviving a long-stalled plan to provide North Korea with fuel in exchange for its closure of the Yongbyon reactor.
"We are now on our way to Pyongyang to negotiate arrangements for IAEA verification for the shutdown and sealing of the nuclear facilities," Olli Heinonen, chief nuclear inspector for the International Atomic Energy Agency (IAEA), told reporters before heading to Beijing's international airport.
"This equals also the sealing and shutdown of the reprocessing plant," he added.
Heinonen said he expected discussions to last three days.
Speaking at the airport, he added: "We are always needing to be optimistic. I think the DPRK will now do what they have (been) asked to do."
Separately on Tuesday, South Korea said it will resume rice aid to impoverished North Korea. Food aid was suspended after Pyongyang defied international warnings and test-fired a barrage of missiles in July 2006. South Korea said it would resume rice shipments from June 30.
North Korea ejected IAEA inspectors in December 2002 and left the nuclear Non-Proliferation Treaty shortly afterwards.
In 2005, North Korea announced it had nuclear weapons, and last year, the country test-detonated its first nuclear device, drawing widespread condemnation and U.N. financial and arms sanctions.
Six-party talks, including the two Koreas, Japan, Russia, the United States and host China, hammered out an accord in February, with the ultimate goal of disabling the Yongbyon complex and completely scrapping the rest of Pyongyang's nuclear program in exchange for massive aid, security guarantees and better diplomatic standing.
North Korea had refused to honor the February agreement until the release of $25 million from Macau's Banco Delta Asia, frozen after the United States blacklisted the bank and accused it of laundering illicit funds for the reclusive country.
Pyongyang confirmed on Monday it had received the funds.