North Korea has cooperated fully with a team U.N. nuclear experts who were monitoring the shutdown and sealing of the country's sole plutonium-producing reactor, the leader of the team said Tuesday.

The 10-member International Atomic Energy Agency team went to North Korea on July 12 to supervise the closing of the Yongbyon reactor, the key component of the North's nuclear program.

"We have a full cooperation with the DPRK authorities," Adel Tolba told broadcaster APTN. The Democratic People's Republic of Korea is the formal name of North Korea.

• Monitor the nuclear disarmament on the Korean Peninsula in FOXNews.com's North Korea Center.

"We finished what was planned. Assessment will be done in Vienna," Tolba said on his departure from Pyongyang airport.

Tolba's team has been replaced by a second six-member IAEA team that arrived in Pyongyang on Saturday.

The IAEA confirmed last week that North Korea had shut down its sole functioning reactor at Yongbyon — the first tangible progress after years of negotiations involving the U.S. and other regional powers.

IAEA inspectors also are working to verify the status of two unfinished reactors, a spent fuel reprocessing facility and a fuel fabrication plant.

The North exploded a test nuclear weapon in October, but four months later agreed to scrap its nuclear program in exchange for economic and political concessions in a deal with the U.S., Russia, China, Japan and South Korea.

It will eventually receive the equivalent of a total of 1 million tons for disabling its nuclear facilities under a February agreement with the five countries.

North Korea has begun receiving oil from South Korea as a reward for shutting down Yongbyon, which is located 60 miles north of Pyongyang.

The shutdown is the first step North Korea has taken to scale back its nuclear ambitions since the crisis began in late 2002.

Complete coverage is available in FOXNews.com's North Korea Center.