The fires were discovered in cardboard boxes at the north and south entrances at around 9.30pm. Staff at the hospital were quickly able to bring the flames under control.
“According to witnesses, there were around eight young guys,” said police spokesman Jan Fryksén.
The gang disappeared from the hospital area but police said they managed to trace a number of suspects.
Six boys, all under the age of 15, were questioned by the police before being taken home to their parents, newspaper Corren reports.
Because of the suspects’ young age, the case is to be handled by the social service authorities.