Five people were shot and killed in the northern German town of Stade, police said on Monday.
The motive was under investigation, they added.
Two people, including a male suspect, were arrested. The role of the second individual in custody is currently unclear.
The attack took place in a youth centre in central Stade, a town of about 50,000 people to the west of Hamburg, local media reported.
Bild reported that all the people killed were adults, and several more had been wounded.
Police urged residents to avoid the area.
