KAMIEN POMORSKI, Poland (AP) — Survivors of a fire that killed 21 people at a three-story shelter for homeless families in Poland on Monday described a fast-moving inferno that forced some to jump from windows into trees. Six of the victims were children and another 20 people were injured, most of whom sustained broken bones after leaping from the building to escape the blaze in the northwestern city of Kamien Pomorski. Poland’s president, meanwhile, raised questions about whether the building met fire regulations. He suggested flammable construction material may have contributed to the fire’s speed and intensity.