Two people have been killed and five others injured in a shooting at a graduation ceremony in Virginia.
The shooting outside the Altria Theater in Richmond sent hundreds of people, many of them wearing graduation gowns, running for safety on Tuesday evening.
"It was obviously chaos," the city's police chief said. "People scattered."
A 19-year-old suspect tried to flee on foot but was arrested. He will be charged with at least two counts of second-degree murder, police said.
The suspect, who has not been named, is believed to have known at least one of the victims. Police did not fire their weapons when apprehending him and several guns were recovered from the scene.
The victims' identities have not been released, but police said the two people killed were an 18-year-old man who was part of the graduating class and his 36-year-old father.
A 31-year-old who was shot sustained life-threatening injuries and is in a critical condition. Four males, aged 14, 32, 55 and 58, were injured but are stable.
The gunman opened fire in Monroe Park, which is directly opposite the theatre, shortly after the ceremony for Huguenot High School had finished at around 17:15 (21:15 GMT).
Families and graduates were leaving the theatre, which is near the campus of Virginia Commonwealth University, when at least eight shots rang out.
People ran to escape, some carrying young children and babies, while others sought cover in nearby buildings. Graduates hugged and cried when they were reunited after the attack.
"This should have been a safe space. People should have felt safe at a graduation," Interim Richmond Police Chief Rick Edwards said at a news conference.
"It's just incredibly tragic that someone decided to bring a gun to this incident and rain terror on our community," he said.
Superintendent of Richmond Public Schools Jason Kamras said the attack occurred on what was "supposed to be a joyous day when our kids walk the stage and get their diploma".
"I don't have any more words on this, I'm tired of seeing people get shot, our kids get shot and I beg the entire community to stop," he said.