The shooting in Dayton in Ohio, came just 13 hours after a mass shooting at a Walmart store in El Paso, Texas, where 20 people were killed and 26 others wounded.
A gunman dressed in body armor opened fire in a downtown district of Dayton, Ohio, early Sunday, killing nine people and wounding at least 26 others, authorities said, in the second deadly mass shooting in the United States in less than a 24 hours.
Police officers who were on routine patrol nearby arrived on the scene in less than a minute and shot the attacker dead, likely preventing a much higher casualty toll, police and the city's mayor said.
"We had officers in the immediate vicinity when this shooting began and were able to respond and put an end to it quickly," Dayton Police Department wrote in a tweet.
Assistant Police Chief Matt Carper told reporters the incident began at 1:00 a.m. local time in Dayton's Oregon District, a downtown historic neighborhood popular for its nightclubs, restaurants art galleries and shops.
The motive behind the shooting was not immediately clear, and investigators believe the individual had acted alone, Carper said. The authorities did not disclose the shooter's identity.
A total of 10 people were killed, including the assailant. Twenty-six others were injured and taken to hospitals across the area, Mayor Nan Whaley told reporters, though the extent of their injuries was not known.
She said the suspect was wearing body armor and was armed with a rifle firing .223-caliber rounds with high-capacity ammunition magazines.
Had police officers not confronted the suspect as quickly as they did, "hundreds of people in the Oregon District could be dead today," the mayor said. FBI agents were assisting in the investigation.
The shooting in Dayton, a riverfront city of about 140,000 people in southwestern Ohio, came just 13 hours after a mass shooting at a Walmart store in El Paso, Texas, where 20 people were killed and 26 others wounded. The 21-year-old suspect in that shooting was arrested.
El Paso Police Chief Greg Allen said investigators were examining a “manifesto” from the suspect indicating “there is a potential nexus to a hate crime.”
A four-page statement posted on 8chan, an online message board often used by extremists, and believed to have been written by the suspect, called the Walmart attack “a response to the Hispanic invasion of Texas.”
The Ohio shooting was the third major outbreak of U.S. gun violence, coming seven days after a teenager killed three people with an assault rifle at a food festival in Northern California before taking his own life.
Pope Francis condemned the attacks on "defenseless people" in the U.S. shootings in his Sunday message and blessing from St. Peter's Square.
The Dayton Daily News said the latest shooting occurred at or near a tavern called Ned Peppers Bar.
The mayor said the carnage in Dayton marked the 250th mass shooting in the United States so far this year, a figure that could not immediately be verified.