BERLIN (AP) — German police say they have arrested four men after finding possible bomb-making material in their car at the border with Austria.

The dpa news agency reported Friday that federal police also suspect the car's 38-year-old Polish driver of trying to smuggle the other three men, ages 20, 29 and 37, into Germany. Police say the passengers are from Ivory Coast and Guinea.

Authorities say they found three pipes in the car, along with what appeared to be gunpowder and possible ignition devices, during a search Thursday night at a border crossing near the town of Kiefersfelden.

Police say the materials could possibly be used to fashion crude pipe bombs, and that experts are trying to confirm whether the substance found is indeed gunpowder.