The explosion occurred shortly after the school day at Hässleholm Technical School began. The school is being investigated by the national bombing experts. Initially the police were investigating he incident as “ongoing fatal violence” but nobody was injured.
The school has about 1,000 students and is the area’s largest senior school, it is not known how many people were at the school at the time of the evacuation.
The noise made by the explosion have been described as ‘powerful’.
The pupils have been evacuated to the dome, a large gathering arena in Hässleholm.
Police arrived at 8:45am and were directed to the school’s basement where the explosion took place.
Swedish STV reporter Mikael Nilsson said some of the students have been shaken by the incident.
He said: “They are relatively ok but clearly shaken over the event. They come to school on a regular day, the school has just begun.
“Then a powerful explosion is heard and the school is surrounded by armed police, rescue and ambulances. It is clear that it makes its mark.”
The police have have said they are not sure if it was a terrorist attack.
Police spokesman Per Cederholm said: “Now we will scan the premises and the place where the perpetrator has been.”
Eva Andersson, Head of Children and Education Administration in Hässleholm, spoke of her sadness at the attack.
She said: “We are just at the end of the semester.
“That someone wants to go in and destroy or put our students in some form of danger feels terrible.”