BERLIN (AP) — German police say 13 people have been injured in an explosion in a factory in Bavaria.

Police said four of those injured in the Monday morning explosion at the Schaeffler factory in the town of Eltmann suffered from serious wounds and were flown by helicopter to a hospital.

Firefighters, police and rescue crews were on the scene but authorities say there appears to be no wider danger for people living in the surrounding area.

The cause of the explosion has not yet been determined.

Schaeffler is a global automotive and industrial parts supplier and the plant in Eltmann produces rolling bearing components. The plant is located in an industrial area of the town, 90 kilometers (55 miles) north of Nuremberg.