A student shot and wounded a fellow student at a Stockholm school on Wednesday, but the motive was not immediately clear, authorities said.
The student wounded at Trangsundsskolan school was initially "awake and able to speak", said police, who opened a "suspected attempted murder" probe.
The school's principal Kaj Majuri said he was aware that the two students had had a conflict some years ago, but that it had apparently been resolved.
Police said the shooting occurred in a "confined space" with "initial information" indicating there were no other people in the immediate vicinity.
Newspaper Aftonbladet said the shooting occurred in a school bathroom.
Some 700 students attend Trangsundsskolan, which runs from grade one to nine with children aged seven to 15.
Shaken students told Swedish media they were told to stay in their classrooms after the incident until given the all-clear.
The two involved in Wednesday's incident were in grades seven to nine, Majuri told reporters, meaning they would be between the ages of 13 and 15.
He said there had been no previous indication that the suspect had violent intentions.
Initially, the Huddinge municipality reported that an air rifle had been used, but it later removed the information from its website.
Sweden has struggled to contain mounting gang violence in recent years, with shootings and bombings now weekly occurrences across the Scandinavian country, including with young assailants.
But Majuri said he was not aware of any connection to gang violence.
"Today there was a conflict between two students that escalated in a serious manner," he told a press conference.
