Thousands mourn Belgrade school shooting victims
STORY: In the pre-planned attack, the 13-year-old shot dead eight plus a security guard, using two handguns that belonged to his father, according to authorities.
Police say the boy fired first at the guard and three girls in a hallway and then shot his teacher and classmates in a history lesson. The teacher and six pupils were hospitalized, some with life-threatening injuries.
Serbia is preparing for three days of national mourning.