Kim Jong Un’s inspection of a secret uranium enrichment site has offered a rare glimpse into the inner workings of North Korea’s nuclear program, a move experts said is aimed at demonstrating Pyongyang’s ability to expand its nuclear arsenal ahead of the U.S. presidential election.

On Friday, state media showed the DPRK leader walking past rows of centrifuges inside a large uranium enrichment facility, the first time he has publicly visited such a site.