North Korea appears to have resumed operation of its plutonium-producing reactor at Yongbyon in a move that could enable the reclusive country to expand its nuclear-weapons arsenal, the U.N. atomic agency said…

“Since early July, there have been indications, including the discharge of cooling water, consistent with the operation of the reactor,” said the report by the International Atomic Energy Agency.

The Yongbyon reactor appeared to have been inactive from December 2018 until the beginning of July 2021, the report noted. It added that signs that the reactor is now being operated coincide with indications that North Korea is also using a nearby laboratory to separate plutonium from spent fuel previously removed from the reactor.

The agency, whose inspectors were kicked out of North Korea in 2009, described the twin developments as “deeply troubling” and a clear violation of United Nations Security Council resolutions.