North Korea's state-run news agency is reporting that the country's main nuclear facility has resumed normal operations and is improving its nuclear weapons in "quality and quantity."

The Yongbyon reactor was shut down in 2007 as part of a disarmament agreement, but Pyongyang had vowed to restart it in 2013, after a third nuclear test raised tensions in the region.

The news agency quoted the director of its atomic agency as saying "If the U.S. and other hostile forces persistently seek their reckless hostile policy towards the DPRK and behave mischievously, the DPRK is fully ready to cope with them with nuclear weapons any time."

Jim Walsh of MIT's Security Studies Program discusses the threats and North Korea's nuclear capability with Here & Now's Peter O'Dowd.

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