STOCKHOLM (AP) — Swedish police say they are investigating a fire that caused major damage to a mosque near Stockholm as possible arson.

Stockholm police spokesman Lars Bystrom says “it appears to have been lit from the outside.” He couldn’t give further details pending an investigation.

No one was injured in the blaze, which started late Sunday. Only a handful of people were in the building but earlier up to 500 people had attended celebrations at the mosque.

Mosque spokesman Akil Zahiri told the national news agency TT on Monday that he was “very troubled” as the mosque wasn’t only his workplace but also “felt like another home.”

As migrants have flooded into Sweden, there have been increasing xenophobic attacks, including 112 fires last year at refugee reception centers, most of them arson.