UN watchdog sees 'serious increase' in North Korea’s nuclear weapons production capacity

North Korea is boosting its nuclear weapons-producing capacity, the chief of the UN nuclear watchdog said in South Korea on Wednesday.

“In our periodic assessments, we have been able to confirm that there’s a rapid increase in the operations” of the Yongbyon reactor, Rafael Grossi, chief of the International Atomic Energy Agency (IAEA), told reporters in Seoul.

“All that points to a very serious increase in the capabilities of the Democratic People’s Republic of Korea (DPRK) in the area of nuclear weapons production, which is estimated at a few dozen warheads,” Grossi said, using North Korea’s official name.

North Korea's Yongbyon Nuclear Scientific Research Center is operating the country’s first nuclear reactors and is located in Nyongbyon County in North Pyongan province, about 62 miles (100 kilometers) north of the capital Pyongyang.

North Korea first conducted a nuclear test in 2006 and has been one of the most sanctioned nations in the world.

Pyongyang has declared its “nuclear status” is irreversible and has cut off access to IAEA officials in 2009.

According to estimates by the Stockholm International Peace Research Institute, North Korea has now assembled around 50 warheads.