Local broadcaster Bayerischer Rundfunk reported, without citing sources, that a suitcase containing several spray cans blew up near the refugee center in Zirndorf, outside the city of Nuremberg.
There was no word on any injuries.
Police told news agency DPA they couldn't confirm or deny that report.
The area is in northern Bavaria, which has seen two attacks claimed by the Islamic State group in the past 10 days.