MILAN (AP) — A van that was transporting oxygen tanks to a nearby medical facility exploded in the center of the Italian city of Milan on Thursday, forcing the evacuation of a school and residential apartment buildings. The driver suffered minor injuries.

Images on Sky TG24 show a plume of dark smoke rising from a narrow street near Porta Romana, where flames scorched nearby cars and motorcycles and exploded windows in adjacent buildings, including the school. Firefighters quickly brought the flames under control.

The driver of the van suffered an injury to his hand when he tried to douse the flames, firefighter Carlo Cardinali told reporters at the scene. The driver was treated at the scene and transported to a hospital.

It wasn’t immediately known what sparked the explosion, but Cardinali said the rapid spread of the flames was due to the quantity of explosive material on board. Law enforcement was investigating.

About 200-300 children at an elementary, middle school and day care complex were evacuated without incident, Milan Mayor Giuseppe Sala told Sky TG24.