The bomber struck shortly after noon in front of a residential building in Gothenburg, Sweden’s largest city.
According to Swedish media reports, 20 to 25 people were injured in the blast, which took place in the southwestern city of Gothenburg’s Annedal district.
Swedish media, particularly the daily newspaper Aftonbladet, put the number of injured at 23, with at least three in critical condition.
Meanwhile, emergency services assisted in extinguishing the fire caused by the blast which affected other buildings.
Families living in the building where the blast took place were evacuated from the building, which numbered between 100 and 200 people.
The Swedish News Agency (TT) reports that 20 people have been hospitalized with injuries, and that authorities are investigating the cause of the blast in central Gothenburg.