Authorities in Sweden suspect foul play after 20 people were injured in an explosion at an apartment complex.

According to the Associated Press, police suspect that an explosive device caused the blast.

The AP reported that the explosion occurred at 5 a.m. Tuesday in the apartment complex's courtyard in Goteborg’s Annedal district.

According to the news agency, eight people were injured and sent to local hospitals for treatment and the evacuation of hundreds.

The AP reported that four people, including three older women and a man in his 50s, were seriously injured.

Police said they were investigating to see if anyone living in the building was a target.