US police fatally shoot teen with replica gun

A police officer in upstate New York fatally shot a 13-year-old who allegedly pointed a replica handgun at officers, authorities say.

Utica Police chief Mark Williams said the shooting happened on Friday night after officers in the city, about 400km northwest of Manhattan, stopped two youths.

One of them ran and pointed what appeared to be a handgun at the officers, he said during a news conference.

One of the officers fired a single shot at the teen "during a ground struggle", striking him in the chest, Williams said.

The teen was given "immediate" first aid by the officers and taken to Wynn Hospital, where he died, the police chief said.

Local media reports identified him as Nyah Mway, a 13-year-old Karen refugee born in Myanmar and an 8th grader at Donovan Middle School.

Lieutenant Michael Curley, a police spokesperson, later confirmed the name.

Karens are an ethnic minority among the groups warring with the military rulers of Myanmar, formerly known as Burma.

In a statement posted online, interim superintendent of the Utica City Kathleen Davis offered condolences to the victim's family.

Davis expressed "profound sadness" over the "tragic and senseless loss" and also offered support to "our partners in law enforcement, who tirelessly strive to ensure our streets remain safe".

Utica mayor Michael Galime said the city would be transparent in its investigation and that he and other officials would meet privately with the teen's family and other community members.

Williams said the Office of the New York State Attorney-General would lead the investigation and determine if it was justified.

According to Williams, the police department will also conduct an internal investigation to determine whether officers followed policies and training.

He said the department is aware of a video of the incident circulating on social media but warned that it does not portray the incident entirely.