A boy who gunned down nine people at a Belgrade school had a list of those he wanted to target, Serbian police said.
Allegedly using his father’s handguns, the 13-year-old shot dead eight pupils and a security guard at Vladislav Ribnikar primary school on Wednesday morning.
Seven others were wounded, including a history teacher and six pupils, some suffering from life-threatening injuries.
Veselin Milic, head of Belgrade police, said the attacker had two guns and two petrol bombs and had carefully pre-planned the attack.
“He even had ... names of children he wanted to kill and their classes," he told a press conference.
The suspect, named by police as Kosta KecmanoviÄ, will be placed in a psychiatric institution, said Serbian President Aleksandar Vucic.
An investigation into the motives for the attack was under way, officials said, as the government declared three days of national mourning.
The suspect’s father, who held the guns legally, had also been arrested.
Serbia’s prosecution service said in a statement that the father would be charged over the shooting but not his son, who was 13, putting him below the legal age of criminal responsibility of 14.
Wednesday’s shooting took place in the central Vracar district of Belgrade.
One pupil, aged 14, told Reuters news agency: “I heard noises and I thought some boys, some kids were throwing firecrackers.... But then I saw the security guard falling to the ground.”
Health Minister Danica Grujicic, a neurosurgeon who witnessed the impact of the Balkan wars, told reporters in tears that Wednesday’s events were “perhaps the most horrifying experience I have had as a doctor and as a human being."
Milan Milosevic said his daughter was in the classroom when the attacker burst in.
“She managed to escape. (The boy) ... first shot the teacher and then he started shooting randomly," Mr Milosevic, who had rushed to the school, told broadcaster N1.
“I saw the security guard lying under the table. I saw two girls with blood on their shirts."
According to the 2018 Small Arms Survey, Serbia globally ranked third with 39.1 firearms per 100 people, and more than 78,000 people have hunting licences.
The survey estimate includes many weapons held illegally since the wars and unrest of the 1990s, despite authorities having issued several amnesties for owners to hand in or register illicit guns.
In the deadliest shooting in Serbia since then, Ljubisa Bogdanovic killed 14 people in 2013. Other mass shootings occurred in 2007, 2015 and 2016.