The man suspected of killing at least six people and seriously injuring more than 30 at a Fourth of July parade in Chicago has been arrested, police have said.
A Highland Park police spokesperson said the suspect, Robert E Crimo III, 22, was spotted by a patrol who tried to initiate a traffic stop.
The suspect fled and after a brief pursuit police were able to stop him and take him into custody.
Police had earlier said he should be considered armed and dangerous.
The attacker opened fire on the crowd in Highland Park, according to officials.
He apparently opened fire from a rooftop using a high-powered rifle which was recovered at the scene, Lake County Major Crime Task Force spokesman Christopher Covelli said.
Mr Covelli confirmed police believe there was only one shooter.
Nancy Rotering, the mayor of Highland Park, said: “This morning at 10.14 our community was terrorised by an act of violence that has shaken us to our core.
“Our hearts go out to the families of the victims at this devastating time.
“On a day that we came together to celebrate community and freedom, we are instead mourning the tragic loss of life and struggling with the terror that was brought upon us.”
According to The Chicago Sun-Times, the parade was stopped after only 10 minutes when shots were fired.
Several witnesses told the newspaper they heard gunfire and that hundreds of parade-goers – some visibly bloodied – fled the route, leaving behind chairs, pushchairs and blankets.
Debbie Glickman, who lives in Highland Park, told Associated Press she was on a parade float with co-workers when she saw people running away from the area.
“People started saying ‘there’s a shooter, there’s a shooter, there a shooter’.
“So we just ran. We just ran. It’s like mass chaos down there.”
One of those killed was a Mexican national, Mexico’s director of North American affairs Roberto Velasco tweeted. He said two other Mexicans were wounded.
J B Pritzker, the governor of Illinois, said: “It is devastating that a celebration of America was ripped apart by our uniquely American plague. I’m furious because it does not have to be this way… while we celebrate the Fourth of July just once a year, mass shootings have become a weekly – yes, weekly – American tradition.”
And Congressman Brad Schneider, who was at the event, tweeted: “My condolences to the family and loved ones; my prayers for the injured and for my community; and my commitment to do everything I can to make our children, our towns, our nation safer. Enough is enough!”
President Joe Biden said in a statement: “Jill and I are shocked by the senseless gun violence that has yet again brought grief to an American community on this Independence Day.
“I recently signed the first major bipartisan gun reform legislation in almost thirty years into law, which includes actions that will save lives.
“But there is much more work to do, and I’m not going to give up fighting the epidemic of gun violence.”