A security guard has died and at least five pupils have been injured after a gunman opened fire at an elementary school in the Serbian capital Belgrade.
Police arrested a seventh-grade student at the Vladislav Ribnikar school in central Belgrade in connection with Wednesday morning's attack.
The suspect is alleged to have used his father's gun, the interior ministry said in a short statement.
An investigation into the motives behind the incident is under way.
Officers in helmets and bulletproof vests cordoned off the area around the school, located in the central Vracar neighbourhood, shortly after 08:40 local time (07:40 GMT).
"The police sent all available patrols immediately to the spot and arrested a suspected minor - a seventh grade student who is suspected of firing several shots from his father's gun in the direction of students and school security," the interior ministry said in a statement.
Local media carried images of what they said was the suspect being led away from the scene by police.
"I saw kids running out from the school, screaming. Parents came, they were in panic. Later I heard three shots," one student told the Serbian state broadcaster RTS.
Mass shootings are comparatively rare in Serbia, which has very strict gun laws, but gun ownership in the country is among the highest in Europe.
The western Balkans are awash with hundreds of thousands of illegal weapons following wars and unrest in the 1990s. In 2019, it was estimated that there are 39.1 firearms per 100 people in Serbia.