Ten people have been killed in a supermarket shooting in Buffalo in the US state of New York, Mayor Byron Brown confirmed on Saturday.
The assailant was arrested, Brown added. He was described as not being from the area.
Three other people were wounded, The Buffalo News newspaper reported online.
Brown said the shooter had travelled to Buffalo from outside the area.
The supermarket is north of the city in area that is mostly home to African-Americans.
The shooter was dressed in body armour and armed with a high-powered rifle, according to The Buffalo News.
Police earlier said the "heavily armed" perpetrator opened fire in the supermarket parking lot before entering the store, where he resumed shooting.
The 18-year-old shooter was white and 11 of the 13 victims were Black, law enforcement officials said at a news conference late Saturday afternoon.
Alleged hate crime
Authorities said that the assailant streamed some or all of the shooting in a live video online.
The shooter may have had a far-right motive for his crime. An investigator on the scene for the FBI said it was investigating the incident as both a hate crime and a case of racially motivated violent extremism.
The Buffalo News quoted Erie County Sheriff John Garcia as saying "It was straight up, a racially motivated hate crime." Garcia added, "This person was pure evil."
"I'm on my way to Buffalo to assist with the response to today’s shooting," New York Governor Kathy Hochul tweeted. "My heart breaks for the victims' families and for everyone impacted by this horrific and despicable act of violence."
Buffalo is the second largest city in the state after New York. The city with around 280,000 inhabitants is only a few kilometres away from Niagara Falls.