KIEV, Ukraine (AP) — A Ukrainian air force commander is being held after his base in Crimea was stormed by pro-Russian forces, and the acting president called for his release Sunday.

Col. Yuliy Mamchur is the commander of the Belbek Air Force base near Sevastopol, which was taken over Saturday by forces who sent armored personnel carriers smashing through the base’s walls and fired shots and stun grenades. One Ukrainian serviceman was reported wounded in the clash.