The police were alerted at around 2:00 a.m. about a suspected explosion at a business premises in Upplands Väsby. When police arrived, they found a fire.
"We don't think anything exploded, but it may have been caused by a flammable object. There was a fire both inside and outside the premises," said police spokesman Mats Eriksson.
The incident is classified as aggravated arson and two people in their late teens have been arrested, the police said on their website.
Police are investigating whether there is any connection to a previous fire in the same area at the end of January.
