(BUFFALO, N.Y.) — At least 10 people are dead and another three wounded after a mass shooting at a supermarket in Buffalo, New York, that authorities said was a “racially motivated hate crime.”

An 18-year-old white, male suspect is in custody, police said. The shooter live-streamed the attack on social media, authorities said.

The gunman, wearing military fatigues, body armor and a tactical helmet, shot four people in the parking lot of a Tops supermarket around 2:30 p.m., three fatally. He proceeded inside the store where he was confronted by a retired Buffalo police officer working security, police said.

The guard shot and struck the suspect, but without effect due to the body armor, police said.

The gunman then proceeded to shoot nine more people inside the store, police said. He threatened to shoot himself before dropping his gun and surrendering to police, authorities said.

Among the 13 victims shot, 11 were African American and two were white, authorities said.

Four of the shooting victims were store employees, while the rest were customers, authorities said. The Buffalo police officer working security was among those killed, according to a law enforcement official.

Three victims suffered non-life-threatening gunshot wounds, authorities said.

The scene is no longer active and no other suspects are outstanding, a law enforcement official said.

The gun was legally obtained but modified with illegal magazines, according to Gov. Kathy Hochul.

“There is no depth to the outrage I’m feeling right now,” she said during a briefing Saturday.

The suspect — identified as Payton Gendron of Conklin, New York — was arraigned on one count of first-degree murder and ordered held without bail Saturday evening, according to Erie County District Attorney John Flynn. His office is also investigating terrorism charges, he said.

The suspect traveled from a New York county several hours away to the Buffalo store, authorities said.

“This is the worst nightmare any community can face,” Buffalo Mayor Byron Brown said at a press briefing Saturday.

The FBI is separately investigating the attack as a hate crime and as racially motivated violent extremism.

Early indications are the shooter may have possessed extremist beliefs cultivated online, law enforcement sources told ABC News.

Investigators are looking at multiple online postings that may be associated with the shooter that include praise for South Carolina church shooter Dylann Roof and the New Zealand mosque shooter Brenton Tarrant, according to the sources.

“This was pure evil,” Erie County Sheriff John Garcia told reporters. “It was a straight-up racially motivated hate crime from somebody outside of our community…coming into our community and trying to inflict evil upon us.”

Flynn said there are pieces of evidence that “indicate some racial animosity,” but would not elaborate more at this point in the investigation.

Hochul said she has directed the New York State Police’s Hate Crimes Task Force to assist in the investigation.

A home associated with the suspect in Conklin, a town near Binghamton in Broome County, was being searched by the FBI and New York State Police Saturday evening, according to law enforcement officials and eyewitnesses. Hochul confirmed during a news briefing that a home in Broome County was being searched Saturday.

Authorities did not specify which social media platform the suspect used to allegedly livestream the shooting. But following the attack, the video game live streaming platform Twitch said it had indefinitely suspended a user over the shooting in Buffalo.

“Twitch has a zero-tolerance policy against violence of any kind and works swiftly to respond to all incidents,” a Twitch spokesperson said in a statement. “The user has been indefinitely suspended from our service, and we are taking all appropriate action, including monitoring for any accounts rebroadcasting this content.”

The company said it removed the stream within two minutes of the violence starting and is monitoring Twitch for any restreams of the content or related content.

Erie County Executive Mark Poloncarz also tweeted Saturday afternoon that he had been “advised of an active multiple shooting event” at the supermarket.

“A horrible day in the history [of] our community,” Poloncarz said in a statement. “Like too many communities in our nation, we’ve been impacted by the horror [of] a mass shooting. My thoughts are about the deceased and with their families at this terrible time.”

President Joe Biden has been briefed on the shooting, his press secretary said.

“He will continue to receive updates throughout the evening and tomorrow as further information develops,” White House press secretary Karine Jean-Pierre said in a statement. “The President and the First Lady are praying for those who have been lost and for their loved ones.”

Attorney General Merrick Garland was also made aware of the incident.

“The Justice Department is investigating this matter as a hate crime and an act of racially-motivated violent extremism. The Justice Department is committed to conducting a thorough and expeditious investigation into this shooting and to seeking justice for these innocent victims,” the statement read.

Tops Friendly Markets said in a statement it was “shocked and saddened” by the shooting and offered condolences to the victims and their families.

“We appreciate the quick response of local law enforcement and are providing all available resources to assist authorities in the ongoing investigation,” the Amherst, New York-based supermarket chain said.

NAACP President Derrick Johnson called the organization was “shattered” and “extremely angered” by the incident.

“This is absolutely devastating. Our hearts are with the community and all who have been impacted by this terrible tragedy,” Johnson said. “Hate and racism have no place in America.”

ABC News’ Matt Foster and Luke Barr contributed to this report.

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