A suitcase exploded near a reception centre for migrants in southern Germany, on Wednesday, but the blast may have been caused by an aerosol can inside it, and there was no evidence of explosives being involved, police said.

The incident in the Bavarian town of Zirndorf, which occurred at around 2.15 p.m. local time, sparked jitters following the spate of violent attacks since July 18 and news of the blast spread rapidly on social media outlets.

Islamic State has claimed responsibility for two of the five attacks.

"Up to now, there is no evidence that the suitcase was detonated by explosives," a police statement statement. "At no point were any people in danger."

A spray can in the suitcase may have triggered the explosion, causing the suitcase to burst into flames, police said.

Police said they were looking for a man around 30 years of age and a woman of about 25 who may have owned the suitcase.