SEOUL, March 3 (UPI) -- The head of the International Atomic Energy Agency warned that North Korea continues operating uranium enrichment facilities and expanding key parts of its nuclear program, calling the developments a "serious concern."

IAEA Director General Rafael Grossi delivered the assessment in his opening statement to the agency's Board of Governors Monday at its headquarters in Vienna, where member states are meeting through Friday.

"The IAEA continues to monitor the nuclear program of the DPRK," Grossi said, using the country's official acronym. "The ongoing operation of enrichment facilities at Kangson and Yongbyon is of serious concern."

Kangson is located near Pyongyang, while Yongbyon -- about 60 miles north of the capital -- houses North Korea's main nuclear complex.

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