The huge blaze in the western city of Duesseldorf on Tuesday completely levelled a hall that housed 282 male asylum seekers mostly from Syria, Iraq, Afghanistan and North African countries, with 28 people suffering from smoke inhalation.
Police have detained eight men allegedly involved in the dispute, including two men suspected of arson, both Moroccans aged 26, one of whom allegedly poured a flammable liquid onto a mattress and set it alight.
"During this time of Ramadan, there was one group that wanted to strictly observe the fast, and another that insisted on the usual timetables and usual servings," said Ralf Herrenbrueck, spokesman for the prosecutors service.
"This had led on several occasions to disputes and altercations with officials of the German Red Cross," he said in an interview with public broadcaster WDR.
"It got to the point where threats were made over what would happen if things didn't change, and that one threat was obviously implemented."
