Two women were killed and five other people were injured when gunfire erupted during a Sunday afternoon barbecue at a park in upstate New York.
Hundreds of people were at the gathering in Maplewood Park, Rochester when someone opened fire around 6.20pm, police said.
“At some point, rounds were fired from multiple weapons, striking the victims,” police chief David Smith said at a news conference.
Tyasia Manning, 25, a city employee, was killed, police said.
A second victim, Phylicia Council, 34, died later.
“I looked up and I hear somebody yell. He’s got a gun! Run!” Rochester resident Shelly Strong told reporters near the scene.
Several police agencies responded, including the Irondequoit Police, Monroe County Sheriff’s Office, Rochester Police and New York State Police.
Police said the gathering had been advertised with flyers.
They did not specify the occasion but said the organisers were not required to obtain a permit from the city in advance.
“There were hundreds of people at this barbecue, and therefore there are hundreds of people who have potential information to help us solve this crime,” Mr Smith said, urging those with video or information to contact police.
No suspects were in custody, police said.
Before the violence, “people were in a celebratory mood, enjoying the warm weather, having a good time”, mayor Malik Evans said on Monday.
He recalled seeing a stroller and people’s shoes at the park in the aftermath.
The mayor added: “Our people, our residents should be able to enjoy the summer in a park. Period. But all too often we have individuals in this community that are unmitigated cowards, that are OK with shooting women. And two of those women lost their life.”
It was the second mass shooting at a Rochester park in as many months.
In June, six people were wounded in an overnight shooting at Dr Martin Luther King Jr Memorial Park.
Mr Smith said at least one person started shooting into a crowd of people during an argument.
In that case, the shooting occurred at an unauthorised gathering when the park was closed.
Captain Greg Bello said it was unknown how many people fired guns during the latest shooting.
“We are trying to work our way through as many witnesses as we can,” he said.
Rochester is about 340 miles northwest of Manhattan.
