People have been seen on CCTV fleeing a masked gunman who killed nine before he was shot dead by police outside a bar in Ohio.
Officers gunned down Connor Betts, 24, after he opened fire in a popular entertainment district in the city of Dayton.
The attack came just a few hours after 20 people were killed in a mass shooting in El Paso, Texas.
Police said Betts, whose 22-year-old sister was among his nine victims, was wearing body armour and carrying a .223-caliber rifle with magazines capable of holding 100 rounds of ammunition.
Footage showed panicked people fleeing from outside a bar as the 24-year-old opened fired.
CCTV later showed police officers shot him dead before he could enter the premises.
Police chief Richard Biehl said the gunman was killed no more than 30 seconds after the attack began.
Bett’s sister Megan was the youngest of the dead.
The other victims were identified 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.
Mayor of Dayton Nan Whaley said at least 27 more people were treated for injuries.
Nikita Papillon, 23, was across the street at Newcom’s Tavern when the shooting began. 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,” Ms Papillon said.
The gunman was a familiar face at another bar in his hometown Bellbrook, southeast of Dayton.
Bartender Andy Baker said he saw Betts at Romer’s Bar & Grill last Monday and seemed fine.
Fellow customer Mike Kern said he sometimes played trivia at Romer’s with Betts, who was good for answers about current affairs and popular culture and was “the kind of kid you’d want as a son”.
He added: “I never heard him talk about violence, say a racist word, or anything like that.”
Bett’s former classmate, Brad Howard, said he had known him for two decades. He said: “The Connor Betts that I knew was a nice kid.”
Betts’ neighbour Stephen Cournoyer added that he often saw Betts mowing the lawn or walking the dog.
Mr Cournoyer said: “He seemed like a good kid. He wasn’t a speed demon, didn’t do anything crazy. But that’s not to say, I mean, obviously he had an issue.”
The gunman was white and six of the nine people 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.
Bellbrook Police Chief Doug Doherty said he and his officers weren’t aware of any history of violence by Betts, including during high school.
They added they had no previous contact with him.
A crowd in Ohio heckled the state governor Mike DeWine during his speech at a vigil following the mass shooting.
Shouts of “make a change” and “do something” were heard as people honoured those killed.
Nine white doves were released as hundreds of people gathered at the scene in Dayton’s Oregon District on Sunday evening.
They sang “Amazing Grace” and erupted in cheers at the mention of emergency responders who had rushed to the scene.
Democratic presidential candidates have accused Donald Trump of encouraging “white nationalism” after the two mass shootings left 29 people dead in the the US.
Suspect Patrick Crusius, 21, was arrested after 20 people were killed at a Walmart store in the Texan city of El Paso, which has a large Hispanic population.