The reasons behind the shooting were "still completely unclear".
On Friday morning, German Chancellor Olaf Scholz described it as a "brutal act of violence", saying his thoughts were with the victims and their relatives.
In a statement, the Jehovah's Witness community in Germany said it was "deeply saddened by the horrific attack on its members at the Kingdom Hall in Hamburg after a religious service". พักยก39
Hamburg's Mayor Peter Tschentscher has spoken of his shock and offered his condolences to the families of the victims.
Forensic experts in white suits worked through the night inside the brightly lit interior of the meeting house.