Members of the U.N.'s nuclear agency on Monday approved sending experts to North Korea to supervise the shutdown of the North's plutonium-producing reactor, a diplomat said.

The International Atomic Energy Agency's board of governors approved the mission at a special session, according to a diplomat who spoke on condition of anonymity because the meeting was closed.

The session focused on an IAEA report compiled by the agency's deputy director general, Olli Heinonen, after a visit late last month to the North's plutonium-producing Yongbyon facility.

The return of the IAEA experts would effectively start the process of ending the North's nuclear program, which — if carried through — would eliminate it as a weapons threat.

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Four months after test-exploding a nuclear bomb, North Korea pledged in February to disable the 5-megawatt reactor, capable of producing enough plutonium to produce one nuclear bomb a year, in exchange for economic aid and political concessions.

That landmark agreement was the result of talks between North Korea and the United States, Russia, China, South Korea and Japan.

But the country refused for months to act on the promise until it received about $25 million in funds that were frozen in a Macau bank in a dispute with the U.S. over alleged money-laundering.

Heinonen's visit was the nuclear watchdog's first trip to the Yongbyon reactor since inspectors were expelled from the country in late 2002.

Click here for FOXNews.com's North Korea center.