PITTSBURGH -- At least eight people have been killed in Saturday morning's shooting at the Tree of Life synagogue in Pittsburgh, according to KDKA.
The shooter surrendered to Pittsburgh police and was being transported to Mercy Hospital, said Curt Conrad, chief of staff for City Councilman Corey O'Connor.
Another law enforcement official told CNN at least 12 people have been shot.
Three police officers were shot, officials said earlier at an impromptu press conference. It's unclear if they are part of those casualties.
The shooter made anti-Jewish comments during the incident, a law enforcement official said.
Pittsburgh police Cmdr. Jason Lando previously said there were "multiple casualties." Officers were dispatched to the scene after receiving reports of active gunfire at the synagogue, he said.
"It is imperative that the neighbors in the community surrounding the Tree of Life synagogue stay in their houses and shelter in place," Lando said. "Do not come out of your home right now. It is not safe."
Fred Rabner, a member of the synagogue, said it was a "close-knit community," and that everyone was calling around to make sure their loved ones are OK.
"Everyone is just shaken up and upset," Rabner said. "It's awful, it's just awful."
Former rabbi: Congregation is a 'vibrant' community
The Tree of Life synagogue is a Conservative Jewish congregation, according to its website. It's in Squirrel Hill, a historic Jewish neighborhood.
The synagogue has a Shabbat service at 9:45 a.m. Saturdays, the website said.
Michael Eisenberg, the immediate past president of the Tree of Life congregation, said three congregations -- Tree of Life, New Light and Dor Hadash -- would have been holding simultaneous services in the building.
There would usually would be about 40 people attending the Tree of Life service in the "main part of the building," Eisenberg said. In the basement below, New Light's service would also have about 30 to 40 people. And the Dor Hadash congregation in the rabbi's study room would have about 15 people, he said.
"On a day like today, the door is open," Eisenberg told a reporter for KDKA. "It's a religious service. You could walk in and out. Only on the high holidays is there a police presence at the entrance."
When he was the congregation's president, security was a "major concern," Eisenberg said.
Chuck Diamond, a former rabbi for the Tree of Life congregation, said, "It's a wonderful Jewish community. Very vibrant, very active."
Shooting 'far more devastating than originally thought,' Trump says
President Donald Trump tweeted he was aware of the situation in Pittsburgh and that law enforcement was on the scene.
"Events in Pittsburgh are far more devastating than originally thought," Trump said in a tweet. "Spoke with Mayor and Governor to inform them that the Federal Government has been, and will be, with them all the way."
Pennsylvania Gov. Tom Wolf said on Twitter that it was a "serious situation," and the Pennsylvania State Police were helping local first responders.
"This is an absolutely tragedy," Wolf said in another tweet. "These senseless acts of violence are not who we are as Americans. My thoughts right now are focused on the victims, their families and making sure law enforcement has every resource they need."
Wolf is on the scene of the shooting, according to a tweet from his verified account.
Carnegie Mellon University issued a shelter in place advisory for its campus, which is near the synagogue.