Authorities say a U.S. Army soldier from Montana's Blackfeet Tribe has died after his humvee struck an improvised-explosive device. Officials with the Blackfeet Veterans Affairs Office say Chief Warrant Officer Lee James Williamson died of complications due to traumatic brain injury. The 44-year-old died Friday. They say the Department of Defense did not say where the explosion occurred. Pentagon spokesman Bill Speaks said Monday he cannot provide details on service-member deaths until next-of-kin has been notified. Williamson and his wife, Sherry Williamson, were based at Fort Bragg. Williamson joined the military after graduating from Fairfield High School in 1988.The tribe says he is to be buried at Fort Bragg.