BERLIN — Three people were hurt on Wednesday in an explosion at an office building in southwestern Germany, police said.

The explosion happened in the afternoon on an industrial estate in the town of Neckarsulm, German news agency dpa reported.

The news agency cited an unidentified security source as saying the blast happened at a building belonging to supermarket chain Lidl, which has its headquarters in Neckarsulm, and it was unclear whether it was caused by a letter bomb.