North Korea ? U.N. inspectors headed to North Korea’s key nuclear reactor today for the first time since 2002 to discuss plans to shut the plutonium-producing facility under an international accord.

The development came as a U.S. official criticized North Korea for conducting test firings of short-range missiles Wednesday, calling them a provocation that could destabilize the region.

Broadcaster APTN reported that the International Atomic Energy Agency team members had left their Pyongyang hotel for the Yongbyon reactor, about 60 miles northeast of the capital.

Olli Heinonen, the deputy director of IAEA, told APTN that his team would tour the Yongbyon facility and discuss specific arrangements for future verification of the reactor shutdown and monitoring. He emphasized that the visit was not a formal inspection.

An inspection would require a formal agreement outlining how it would be conducted, subject to approval by the Vienna-based IAEA board of governors, he said Wednesday.