German authorities say a billionaire businessman's son was kidnapped and held overnight before being released unharmed without payment of the millions of euros demanded.

Markus Wuerth, the 50-year-old son of the Wuerth tool and hardware company chairman Reinhold Wuerth, was abducted on Wednesday in an area northeast of Frankfurt.

Giessen state prosecutors' spokesman Thomas Hauburger said he was found Thursday morning in a forest about 100 kilometers (60 miles) southeast of where he was seized. Hauburger says he was unharmed, and a multi-million euro ransom was demanded but not paid.

The kidnapping prompted a police manhunt, which may have prompted Wuerth's release.

Hauburger wouldn't identify the kidnap victim, but Wuerth spokeswoman Sigrid Schneider confirmed it was the chairman's son.

Police are still searching for the kidnapper or kidnappers.