The mayor of Ansbach, a town near the German city of Nuremberg, said an explosive device has killed one person and injured at least 10 others.
Mayor Carda Seigel said the explosion happened late July 24 near the entrance to an open-air music festival.
Other reports put the scene of the explosion at a restaurant or bar.
Police have cordoned off the area and emergency vehicles were reportedly at the location of the blast.
Bavarian Interior Minister Joachim Hermann was reportedly on route to the scene of the explosion.
Germany is on edge following several recent incidents of violence.
Earlier on July 24 an asylum-seeker from Syria killed a woman with a machete and injured two other people in the southwestern city of Reutlingen before being arrested by police.
An 18-year-old German-Iranian shot dead nine people in Munich on July 22 and on July 18, a 17-year-old asylum-seeker from Pakistan wounded five people on a train using an ax and knife.