Swedish police said at least two people were injured and one person has been arrested in Malmo during an after-school incident at a high school.
Police said the situation was under control, adding they had responded to “a suspected serious crime”. The Aftonbladet newspaper said students were being kept inside the classrooms.
Police said they got the alarm at 5:12pm local time. Armed police were seen entering Malmo Latin School, which was cordoned off, Swedish broadcaster SVT reported, adding it was unclear what had happened but that several people were reported injured.
It said students had gathered to work on a musical.
There were several ambulances outside the school, which has 1,100 students, Aftonbladet wrote.
“This is absolutely terrible,” school principal Fredrik Hemmensjo told the daily.
The incident took place in a modern annex of the school, which was founded in 1406 when the pope issued a letter of privilege allowing for its construction and operation.
It was originally meant to educate local youth on Christian doctrine and the Latin language.