Two neighboring houses in Wallerstein caught fire on Wednesday evening, with the blaze injuring 12 people.

Police arrested a 22-year-old man who was present at the location when fire broke out. The suspect has denied all accusations of arson.

Residents called rescue services after fire broke out in the cellars of the two buildings. According to the police, one of the cellars was strewn with litter and was completely destroyed in the fire. The cellar of the second house burst into flames around the same time.

The buildings were not refugee homes, but many inhabitants were from Poland and Italy and several others were German nationals, leading officials to believe that there might have been an anti-foreigner sentiment behind the attack, a police spokesman told journalists. However, there was no concrete proof indicating an anti-immigrant motive, he added.

The suspect was also heavily drunk when officials caught him. "It could be that he didn't know who was living in the house," the spokesman said. The man was not a resident of Wallerstein.

Wallerstein's mayor, Joseph Mayer told Bavaria's official broadcaster Bayerische Rundfunk that he did not believe in any anti-immigrant sentiment fueling the attack. The 22-year-old could have been acting out of frustration when he couldn't meet his friend. He was roaming around drunkenly when he "coincidentally came across an open window or a door," Mayer told journalists.

Nearly one million refugees fleeing conflict and poverty in the Middle East and Africa have arrived in Germany this year. Although a majority of Germans have been welcoming, several right-wing and anti-immigrant groups have shown their displeasure by protesting and sometimes even attacking refugee shelters.

mg/rc (AFP, dpa)