Police were investigating a fire that damaged the prayer room of a mosque in western Germany on Thursday, and were not ruling out arson. A window was broken at the mosque, but it was not clear whether something like a fire bomb had been thrown inside, said police spokesman Sigfried Schlott. "We are investigating in all directions," he said. The mosque opened earlier this year in Usingen, a city in the state of Hesse north of Frankfurt. The fire was reported at 5:20 a.m. by a passer-by who spotted smoke coming from the first floor, and the fire department was able to put it out quickly. Nobody was injured, but the blaze caused an estimated ¤50,000 (US$67,000) in damage.