The attacker reportedly used two kitchen knives to wound three teachers and two pupils.
A 14-year-old student at a high school in the southern Spanish town of Jérez de la Frontera has been arrested after wounding three teachers and two pupils with a knife.
At 8.25 a.m. on Thursday, the National Police received a call alerting them that an armed individual was attacking people, the police said.
The pupil entered the classroom "angry" and sat down at the back, then took "knives" from his backpack, one of his classmates told EFE news agency.
The attacker had two kitchen knives with which he assaulted classmates and teachers.
They all suffered injuries of "varying severity", according to police sources. One of the teachers is in a serious condition with an eye injury.
Another student, who suffered minor injuries, has already left the hospital where he was taken this morning.
According to El País, the assailant attacked one of his classmates from behind and stabbed him with two knives, shouting 'I'm going to kill you'.
The rest of the class ran out and the biology teacher, who was in the room at the time, went to the teenager and told him to "please stop".
The boy then reportedly attacked her eye.
He then left the room and went to another classroom. According to a pupil who spoke to El País, one teachers and several students managed to stop him.
The EFE news agency, which was able to speak to another pupil at the school, said the aggressor "is not a problematic person, but he is always alone, he has 'a thing', I think he has lost his mind".
The minor could have a mental disorder, according to his classmates, who have claimed in the media he suffers from Asperger's syndrome.
They also said the child may have been bullied because "some of his classmates laughed at him", "others threw water on him in the playground".
All pupils have been evacuated from the school while police continue to investigate.