Two people were killed and 14 others wounded in a shooting in Rochester, New York, police said on Saturday.

The shooting appeared to start at a backyard party just before 12:30 a.m., with about 100 people running to and from a "very chaotic scene", said Rochester Interim Police Chief Mark Simmons.

"We have 16 confirmed victims of shooting. And I'm sad to announce that two of those 16 received a fatal wound," Simmons said at a news conference.

The two people killed were a man and woman in their late teens or early 20s, he said.

Simmons said it was unclear if the shooting was a targeted or random act of violence. The wounded were being treated in hospital and their injuries were not thought to be life threatening.