Three gunmen have shot eight people including a three-year-old girl on an east Baltimore street.
The Maryland city's police commissioner said the suspects fled and the victims were expected to survive.
The shooting erupted outside some terraced houses about 8.30pm on Saturday after the armed men converged on the group from different points, Kevin Davis said at the scene.
Mr Davis said it was a premeditated act of retaliatory violence in response to a Labour Day weekend shooting in which a person was shot dead and two others wounded, including a pregnant woman.
He said the victims could have recognised the gunmen but authorities had not immediately been able to identify the suspects and were still searching for them hours later.
One of the armed men emerged from an alley and two others ran down the street, stopping just short of the victims before they opened fire, he said.
The 3-year-old girl and her father were standing away from the group and the child was not an intended target, Mr Davis said. Authorities tweeted that one man had a shotgun and the other two had handguns.
Other victims were a woman and the rest were men. Aside from the girl, the ages of the victims ranged from 26 to 39, according to police.
The shooting occurred just a street from where the city held a party earlier on Saturday for a special event. Police said the attack was unrelated to the party in which the city dedicated a project called Open Works, billed as an innovative work space.
At the scene, police sealed off at least three streets and were keeping bystanders away as Mr Davis spoke to detectives at the scene.
Nearby, police were seen using flashlights as they searched tall, overgrown grass in an alley near the shooting site.
Police cars blocked a nearby junction and crime scene tape secured the area.