An "extreme danger" alarm was sounded in Germany's Hamburg and the police asked the residents to stay indoors as shots were fired upon a religious gathering in a church on Thursday.
At least seven persons were killed and eight others seriously injured in the attack on a weekly Bible study meeting at a Jehovah's Witness centre, local reports said.
Jehovah's Witnesses is a US Christian movement that preaches non-violence and practise door-to-door evangelism.
A gunman is believed to be among those killed, police said, without releasing any casualty figure.
The police used a catastrophe warning app to send out the danger alarm while nearby buildings were cordoned off.
We found a lifeless person in a community center who we believe could be a perpetrator, Hamburg Police tweeted, adding that searches are still on for the involvement of other attackers.
(With inputs from AFP and Reuters)
Track Latest News Live on NDTV.com and get news updates from India and around the world
