( CNN ) -- A bus carrying members of a Marine Corps Reserve unit overturned at an Alabama military base Sunday , leaving 23 Marines injured , four of them critically , the military said in a news release . A bus overturned Sunday in Alabama , injuring 23 Marines , the military said . The passengers , members of E Company , Anti-Terrorism Battalion , 4th Marine Division , had been taking part in a training exercise at Fort Rucker , an Army post outside Ozark , Alabama . They were departing the range at 9:20 a.m. when the accident occurred . The unit is made up of reservists from Tallahassee , Florida , and Bessemer , Alabama . The injured were from First and Headquarters Platoons out of Bessemer , a Birmingham suburb . By mid-afternoon , 11 of the injured had been released to their unit from the hospital . Pictures of the wreck were provided to the news media by the military . Ozark is about 175 miles south of Birmingham . E-mail to a friend .
Bus carrying Marine Corps Reserve unit overturned at Alabama military base . 23 Marines have been injured ; four critically , the military says . Score: 6 The accident happened Sunday morning , officials said .