An 18-year-old gunman has allegedly shot dead 10 people in what police say is a "racially motivated" incident.
The shooting took place at a supermarket in the New York city of Buffalo on Saturday afternoon (local time).
Three other people were shot but not killed. Eleven of the 13 people shot were black.
The suspect, who witnesses say was wearing army-like attire, allegedly livestreamed the shooting on the internet.
Authorities described the incident as "extremism".
"This person was pure evil," Erie County Sheriff John Garcia said at a news conference, his voice quaking with emotion.
"It was a straight-up racially motivated hate crime from somebody outside of our community."
The alleged gunman has been detained and has been charged with first degree murder.
He was reportedly involved in a shootout with the store's security, however he was unaffected by their bullets due to bullet proof clothing, the ABC reported.
The security guard is one of the 10 victims.
The shooting took place at Tops Friendly Market with a store manager telling local media she heard about 70 gunshots. The terrified worker said she stumbled several times as she fled.
"This is a day of great pain for our community," Buffalo Mayor Bryon Brown told reporters.
"Many of us have been in and out of this supermarket many times. ... We cannot let this hateful person divide our community or our country."
Brown said he had received calls from the White House and New York's attorney general, Letitia James.
US Representative Jerry Nadler, a New York Democrat and chairman of the House Judiciary Committee, said the attack appeared to be the work of a violent white supremacist.
"We must pass the Domestic Terrorism Prevention Act, without delay," he wrote on Twitter.
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