North Korea’s continued development of its nuclear and missile programs remains a substantial threat to American forces and allies in the region, the head of U.S. Strategic Command said on Tuesday.

Admiral Charles A. Richard’s remarks come amid a U.N. report leak this week, which indicated that experts now believe North Korea has miniaturized its nuclear weapons and is continuing to develop its nuclear and ballistic missile weapons, despite sanctions.

“North Korea continues its illicit pursuit of nuclear weapons and [is] advancing their missile systems,” Richard said during an online broadcast for the Space and Missile Defense Symposium on Tuesday.