WARSAW, Poland (AP) — Polish firefighters say six people have died in a fire at a small wooden building sometimes used by the homeless in an outlying district of Warsaw.

Pawel Fratczak, a spokesman for firefighters, said Wednesday the fire took place late on Christmas Day. When firefighters arrived at the scene, the small wooden building was in flames and they found six bodies.

Fratczak said the cause of the fire is not known but police and prosecutors have opened an investigation.