Suicide bombers then drove cars packed with explosives into the prison gates, while gunmen followed up machine-gun fire and rocket-propelled grenades. At Abu Ghraib, several militants wearing suicide vests ran into the prison to help free inmates, while other fighters took up ambush positions nearby to fend off the Iraqi government's efforts to send in reinforcements. It took ten hours for the Iraqi government, which despatched helicopter gunships to the scene, to restore order. Officials said that at least 20 members of the security forces and around 21 inmates, with the final death toll expected to rise.