At least 10 have been killed in the mass shooting in Buffalo.
The FBI is investigating it as both a hate crime and racially motivated violent extremism.
US media reports indicate the suspect is a white supremacist. The mayor says he “traveled hours from outside this community to perpetrate this crime on the people of Buffalo.”
Some reports say the suspect posted a manifesto online that included antisemitic ranting.
“We are investigating this incident as both a hate crime and a case of racially motivated violent extremism,” Stephen Belongia, special agent in charge of the FBI’s Buffalo field office, tells a news conference.
The supermarket is in a predominately Black neighborhood, about 3 miles (5 kilometers) north of downtown Buffalo.
Investigators believe the gunman may have been streaming the shooting through a camera affixed to his helmet, an official says.