DAYTON, Ohio >> Nine people in Ohio have been killed in the second mass shooting in the U.S. in less than 24 hours, and the suspected shooter is also deceased, police said.

Dayton police tweeted that an active shooter situation began in the Oregon District at 1 a.m., but officers nearby were able to “put an end to it quickly.” Lt. Col. Matt Carper said at a press conference that the suspect was shot to death by responding officers.

At least 16 others were taken to local hospitals with injuries, police said. No details about the victims were released.

Police believe there was only one shooter, and have not yet identified the suspect or a motive. Carper said the suspect used a long gun and fired multiple rounds.

Miami Valley Hospital spokeswoman Terrea Little said 16 victims have been received at the hospital, but she couldn’t confirm their conditions. Kettering Health Network spokeswoman Elizabeth Long said multiple victims from a shooting had been brought to system hospitals, but didn’t have details on how many.

With a population of around 140,000 Dayton is in western Ohio, around 55 miles (90 kilometers) northeast of Cincinnati, 75 miles (120 kilometers) west of Columbus and 120 miles (195 kilometers) east of Indianapolis. The Oregon District is a historic neighborhood that Carper described as “a safe part of downtown,” home to entertainment options, including bars, restaurants and theaters. The shooting took place outside, on the 400 block of East 5th Street.

“This is extremely unusual, obviously, for any community, let alone Dayton,” Carper said. “In our Oregon District, this is unheard of.”

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

“I’m heartbroken,” Dayton Mayor Nan Whaley tweeted around 6 a.m. Sunday, thanking first responders for their efforts.

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.