A student walked into a secondary school in Kahramanmaras province in southeastern Turkey on Wednesday and opened fire in two classrooms, leaving three fellow students and a teacher dead while wounding 20 others.
The attacker then took his own life.
The incident happened at Ayser Calik Secondary School in the Onikisubat district of Kahramanmaras.
Officials say the eighth-grade student, who was around 13 or 14 years old, carried several handguns and magazines in his backpack.
The weapons belonged to his father, a retired police officer.
Governor Mukerrem Unluer told reporters that the student entered classrooms where younger pupils were present and fired at random.
Four of those injured remain in a serious condition and are undergoing surgery.
This event comes just one day after another school shooting in Siverek, in Sanliurfa province.
In that case, a former student opened fire at his old high school, wounding 16 people including students and teachers before he killed himself during a confrontation with police.
School shootings of this kind remain uncommon in Turkey, though authorities have now stepped up security measures at educational institutions across the country.
Prosecutors have launched an investigation into both attacks to establish the full details and any possible motives.
Parents rushed to the scene in Kahramanmaras as news spread, and emergency teams quickly arrived to help those hurt.
Videos from the area showed ambulances leaving the school grounds and people waiting anxiously outside.
Turkish officials have not yet released the names of the victims or the attacker.
Further updates are expected as the inquiry continues.
