VIENNA, Austria -- Police say an arsonist targeted three churches in an Austrian town around the same time -- one of them during a service -- but nobody was injured.

Austrian news agency APA cited police as saying that about 100 firefighters were successively deployed to the churches in the town of Amstetten on Saturday to contain the small blazes, which caused minor damage.

Regional firefighter spokesman Franz Resperger said the attacker apparently tried to set the entrance at one church ablaze while a service was being held.

Police ordered heightened security measures for churches in the town some 130 kilometres (80 miles) west of Vienna throughout the Christmas holidays.

Regional police head Franz Prucher said there was a reward of (euro)3,000 for tips leading to the perpetrator's arrest. The motive was unclear.