The tragic and deadly bombing of a Doctors Without Borders hospital in Afghanistan was "the direct result of avoidable human error," a high-level U.S. military leader said Wednesday U.S. Army Gen. John Campbell, the top U.S. commander in Afghanistan, said at a news conference that the fatal mistake was "compounded by systems and procedural failures," NBC News reported. Issues included a failure to brief the crew and technical problems on the plane. At least 30 people were killed when the hospital in Kunduz was hit by U.S. military airstrikes in October. Fourteen staff members working with the charity medical organization were among the dead.Campbell had previously said the hospital was struck by mistake. But a report detailing the findings of the U.S. investigation into the bombing, which was obtained by The Associated Press , sheds more light on what happened. Investigators found that U.S. forces mistook the hospital for a suspected Taliban prison that was actually 450 yards away, according to the AP Doctors Without Borders, known internationally as Médecins Sans Frontières, or MSF, has repeatedly condemned the bombing and called for an independent international probe into the attack . Officials with the group say they had informed U.S. and allied forced of their coordinates just days before the airstrikes.