(CNN) — Seven people were killed during a mass shooting on Thursday at a Jehovah’s Witnesses Kingdom Hall in the German city of Hamburg in what the country’s leader denounced a “brutal act of violence.”

”Eight people are dead – including the alleged perpetrator,” Hamburg police said in their latest statement. “Other people were injured in the incident, some seriously.”

The Jehovah’s Witnesses in Germany said in a statement: “The religious community is deeply saddened by the horrific attack on its members at the Kingdom Hall in Hamburg after a religious service.”

The slayings in the northern German city occurred around 9 p.m. local time (3 p.m. ET) with police initially unsure how many shooters might be involved.

But later updates from the city’s police force suggested there was just one attacker, who may have died at the scene.

“At present, we believe there is one perpetrator,” Hamburg police said in their latest update on their Twitter account, hours after armed officers scoured the scene for evidence and suspects.

“All police measures in the vicinity are being successively discontinued. The investigation into the circumstances of the crime continues.”

Chancellor Olaf Scholz led politicians in denouncing the murder spree in the northern German city.

“Several members of a Jehovah community fell victim to a brutal act of violence last night. My thoughts are with them and their loved ones,” he wrote on Twitter.

A police spokesperson earlier said that authorities were investigating whether the shooter was among the several people found dead at the scene.

After being called to the building, police saw dead and injured people on the bottom floor where an event was taking place, Hamburg police spokesman Holger Vehren told NTV.

Officers also heard a shot on the top floor of the building when they first entered it and found a dead person upstairs.

Police believe it may have been the shooter but said no further information could be given at this point, a spokesperson said.

Footage from the scene showed numerous armed police officers inside and around the Kingdom Hall while a helicopter flew overhead. A bomb disposal team was deployed at one point.

The streets around the place of worship have been cordoned off, and police earlier warned of “extreme danger” in the area, the spokesperson added.

Nearby residents have been urged to stay indoors.

There is “no confirmed information on the motive for the crime,” police said on Twitter as they urged people not to share any unconfirmed assumptions.

Hamburg Mayor Peter Tschentscher expressed his “deepest sympathy” for the relatives of the victims, calling the reports of the incident “shocking” on Twitter.

Messages of support came in from Hamburg’s religious communities.

“The news of this bloody crime in Hamburg-Alsterdorf is shocking and leaves me speechless… My deepest sympathy goes to the relatives of the victims,” Father Sascha-Philipp Geißler, a senior member of Hamburg’s Catholic diocese, said in a statement.

Shootings in Germany are not unheard of, though rarer than in the United States

In January 2022, at least one person was killed after man opened fire on students in a lecture hall at Heidelberg University in southwestern Germany.

In 2020, a mass shooting at two shisha bars in Hanau killed several people.

Seven dead in shooting at a Jehovah’s Witnesses center in Germany