The North Korean leader made the announcement while inspecting a new warship, alongside by his teenage daughter ahead of a visit by Chinese President Xi Jinping .

Kim Jong Un has vowed to accelerate efforts to build a nuclear-armed navy and develop ‘secret underwater weapons’. The North Korean leader was accompanied by his teenage daughter, believed to be named Kim Ju Ae,

Kim Jong Un inspected a new plant that makes weapons-grade nuclear material on Wednesday and said Pyongyang plans to “beef up our state’s nuclear forces at an exponential rate,” according to a report from state-run media.

North Korean leader Kim Jong Un visited a newly inaugurated nuclear materials production facility and vowed "exponential" growth, state media reported Thursday.

Footage showed the North Korean leader smiling as he congratulated the players of Naegohyang Women's FC.