A Bangladesh Air Force F-7 BGI training jet crashed into the Milestone School and College campus in Dhaka’s densely populated Uttara district on Monday, killing at least 31 people—about 25 of them children—and injuring more than 160, according to health-ministry and military officials. The aircraft exploded on impact, setting the two-storey school building ablaze while classes were under way. The Chinese-built single-engine fighter had taken off from the nearby A.K. Khandaker air base at 1:06 p.m. on a routine training mission. The military said the pilot, Flight-Lt. Towkir Islam—who also died—reported a technical malfunction moments after take-off and tried to steer the jet away from residential areas before losing control. Bangladesh operates 16 F-7 BGI aircraft, delivered between 2011 and 2013. Firefighters, soldiers and volunteers evacuated more than 170 students and staff from the burning campus. Health officials said 78 people remain in hospital, many with severe burns. Interim leader Muhammad Yunus declared Tuesday a national day of mourning and ordered an inquiry headed by the armed forces to determine the cause of the crash. Grief quickly turned to anger as hundreds of students demonstrated near the school and outside government offices on Tuesday, demanding publication of the full casualty list, compensation for families and a halt to training flights over populated districts. Police maintained a heavy presence while investigators combed the wreckage for flight data and cockpit recordings.