A seven-year-old girl has died and a teacher and five other students were wounded in a knife attack at a school in the Croatian capital, authorities say.
Police said the attack happened on Friday morning at the Precko Elementary School in the neighbourhood of the same name.
They described the attacker as a "young male" and said he had been detained.
Health Minister Irena Hristic said the attacker was over 18, while media reported he was 19.
Video published by Croatian media showed children running away from the school building in Zagreb and a medical helicopter landing in the schoolyard.
Prime Minister Andrej Plenkovic said he was "appalled" by the attack and authorities were still working to determine exactly what happened.
Plenkovic said several children had been taken to various hospitals in Zagreb.
State HRT television said the attacker entered the school and went straight into the first classroom he found and attacked the children.
School attacks are rare in Croatia.
Last May, a teenager in neighbouring Serbia opened fire at a school in the capital Belgrade, killing nine fellow students and a school guard.