BERLIN — Several people were dead and several more injured in a shooting in a Jehovah’s Witness Hall in Hamburg on Thursday, in what appears to be a rare mass shooting in Germany.

The police, including tactical units, were on the scene late Thursday, and the injured were rushed to local hospitals.

Little was immediately known about the assailant or assailants. A police spokesman indicated that the assailant had not been found and might be among the dead.

“All we know is that several people died here and that several people have been injured and have been brought to hospitals,” a Hamburg police spokesman said.

Authorities have issued a warning, asking people to avoid the area and stay indoors.

This story is developing and will be updated.