A shooting at a Jehovah's Witness centre in the German city of Hamburg has left eight people dead, including the suspected gunman, police said Friday, as the motive for the attack remained unclear.

Several more people were wounded in the attack late Thursday at the Kingdom Hall building in the port city of Hamburg, where Jehovah's Witness members were attending a religious service.

"Eight people were fatally injured, apparently including the suspected perpetrator," Hamburg police said, adding that several other people were hurt, "some seriously".

German media put the number of wounded people at eight.

News weekly Der Spiegel reported that the suspected attacker was a former member of the Jehovah's Witness community who was not a known extremist.

The magazine, which did not cite its sources, said he had been armed with a handgun.

Best-selling newspaper Bild named the suspect as 35-year-old "Philipp F." and said he killed himself after police stormed the building.

Chancellor Olaf Scholz condemned the "brutal act of violence" and said his thoughts were with the victims and their loved ones.

- 'Filmed the whole thing' -

The Jehovah's Witnesses in Germany association said it was "deeply saddened by the horrific attack on its members".

Hamburg police are due to give an update at a press conference around midday and urged people not to speculate about the motive behind the shooting.

Interior Minister Nancy Faeser said investigators were "working flat-out to determine the background" to the attack.

The first emergency calls were made around 9:15 pm (2015 GMT) on Thursday after shots rang out at the building in the city's northern district of Gross Borstel.

An alarm for "extreme danger" in the area was sounded using a catastrophe warning app, but Germany's Federal Office for Civil Protection lifted it shortly after 3:00 am on Friday.

Neighbours in the area recalled hearing multiple shots fired late Thursday.

"Our son filmed the whole thing, he could see quite well from the house," Bernd Mibache, a 66-year-old business owner, told AFP.

"On the video you can see that someone broke a window, you can hear shots fired and see that someone broke in."

- 'Something big' -

Police have asked witnesses to come forward and upload any pictures or videos they may have to a special website.

Another resident said police arrived on the scene within "four or five minutes".

"We heard shots and we knew something big was happening," said the woman, who gave only her first name Anetta.

She said she knew the building was used by members of the Jehovah's Witness community, describing them as "very peaceful, quiet".

The three-storey building was still cordoned off on Friday with several officers standing outside, an AFP reporter said.

Germany has about 175,000 Jehovah's Witnesses, including 3,800 in Hamburg. The US Christian movement, set up in the late 19th century and which preaches non-violence, is known for door-to-door evangelism.

The first officers to enter the Jehovah's Witness Kingdom Hall building found several lifeless bodies and seriously wounded people, police said.

- Hit by attacks -

Officers heard a shot in the "upper part of the building" before finding a body in the area where it rang out, police said.

In a tweet, Hamburg police said they assumed the body belonged to the perpetrator. The suspect is believed to have acted alone.

Germany has been rocked by several attacks in recent years, both by jihadists and far-right extremists.

Among the deadliest committed by Islamist extremists was a truck rampage at a Berlin Christmas market in December 2016 that killed 12 people.

The Tunisian attacker, a failed asylum seeker, was a supporter of the Islamic State jihadist group.

Germany has also been hit by a string of far-right assaults, sparking accusations that the government was not doing enough to stamp out neo-Nazi violence.

In February 2020, a far-right extremist shot dead 10 people and wounded five others in the central German city of Hanau.

In 2019, two people were killed after a neo-Nazi tried to storm a synagogue in Halle on the Jewish holiday of Yom Kippur.