Three schoolchildren including two sisters were killed and 13 others sustained injuries when a truck collided with a school van at Pakpattan road near here on Saturday. Reportedly, a van (SLE-2012) was carrying schoolchildren including boys and girls to drop them at homes after school time when a rashly driven truck (LHT-6797) coming from opposite direction by violating one-way traffic collided with it near Bulleh De Jhok.