DAYTON, Ohio — A gunman in body armor opened fire early Sunday in a popular entertainment district in Dayton, Ohio, killing nine people, including his sister, and wounding dozens of others before he was quickly slain by police, city officials said.

Connor Betts, 24, was killed by police less than a minute after he started shooting a .223-caliber rifle in the streets of Dayton’s historic Oregon District about 1 a.m. in the second U.S. mass shooting in less than 24 hours. Police haven’t released further information about Betts or publicly discussed a motive.

Surveillance video shared by police showed officers shot Betts at the doorstep of further destruction, just stopping him from entering a bar where some people took cover when the chaos broke out.

His 22-year-old sister Megan was the youngest of the dead — all killed in the same area of bars, restaurants and theaters that is considered a safe area downtown, police said.

Officials said the shooter was wearing a bulletproof vest, mask, and hearing protection, and carried at least 100 rounds.

Had police not responded so quickly, Dayton Mayor Nan Whaley said, “hundreds of people in the Oregon District could be dead today."

The gunman was white and six of the nine killed were black, police said. Although they’ll investigate the possibility of a hate crime, they said the quickness of the rampage made any discrimination in the shooting seem unlikely.

The Oregon District is a historic neighborhood that Lt. Col. Matt Carper described as “a safe part of downtown,” home to entertainment options, including bars, restaurants and theaters.

Authorities identified the other dead as Monica Brickhouse, 39; Nicholas Cumer, 25; Derrick Fudge, 57; Thomas McNichols, 25; Lois Oglesby, 27; Saeed Saleh, 38; Logan Turner, 30; and Beatrice N. Warren-Curtis, 36.

Whaley said at least 27 more people were treated for injuries, and at least 15 of those have been released. Several more were in serious or critical condition, hospital officials said at a news conference Sunday morning. Some suffered multiple gunshot wounds and others were injured as they fled, the officials said.

Betts was from Bellbrook, southeast of Dayton. Bellbrook Police Chief Doug Doherty said he and his officers weren’t aware of any history of violence by Betts, including during high school.

Nikita Papillon, 23, was across the street at Newcom’s Tavern when the shooting started. She said she saw a girl she had talked to earlier lying outside Ned Peppers Bar.

“She had told me she liked my outfit and thought I was cute, and I told her I liked her outfit and I thought she was cute,” Papillon said. She herself had been to Ned Peppers the night before, describing it as the kind of place “where you don’t have to worry about someone shooting up the place.”

“People my age, we don’t think something like this is going to happen,” she said. “And when it happens, words can’t describe it.”

Tianycia Leonard, 28, was in the back, smoking, at Newcom’s. She heard “loud thumps” that she initially thought was people pounding on a dumpster.

“It was so noisy, but then you could tell it was gunshots and there was a lot of rounds,” Leonard said.

Gov. Mike DeWine issued his own statement before 7 a.m., announcing that he’s ordered flags in Ohio remain at half-mast and offered assistance to Whaley.

“Fran and I are absolutely heartbroken over the horrible attack that occurred this morning in Dayton, the statement said. “We join those across Ohio and this country in offering our prayers to victims and their families.”

Sen. Sherrod Brown (D-Ohio) says responding with thoughts and prayers isn't enough, and stronger gun safety laws are needed.

Sen. Rob Portman (R-Ohio) says he saw workers cleaning blood off the sidewalks when he visited the scene in Dayton's Oregon District. He says it's an unspeakable tragedy and the discussion needs to include not just policy changes, but issues such as mental health supports.

The FBI is assisting with the investigation. A family assistance center was set up at the Dayton Convention Center.

The Ohio shooting came hours after a young man opened fire in a crowded El Paso, Texas, shopping area, leaving 20 dead and more than two dozen injured. Just days before, on July 28, a 19-year-old shot and killed three people, including two children, at Northern California’s Gilroy Garlic Festival.

Sunday’s shooting in Dayton is the 22nd mass killing of 2019 in the U.S., according to the AP/USA Today/Northeastern University mass murder database that tracks homicides where four or more people killed — not including the offender. The 20 mass killings in the U.S. in 2019 that preceded this weekend claimed 96 lives.