The U.S. Department of Justice (DOJ) is investigating the mass shooting in Buffalo, New York State, as a hate crime.
U.S. Attorney General Merrick Garland said in a statement on Saturday night that the nation mourns the victims of "a senseless, horrific shooting" and the DOJ "is investigating this matter as a hate crime and an act of racially-motivated violent extremism."
He vowed to conduct "a thorough and expeditious investigation into this shooting" and to seek "justice for these innocent victims."
Federal law enforcement agencies, including the FBI, are working with Buffalo Police Department and other partners, according to Garland's statement.
At least 10 people were killed by a gunman in a supermarket in Buffalo on Saturday afternoon. Three others were wounded but are expected to survive.
The gunman, who's in custody, wore military-style clothing and body armor and opened fire with a rifle. The attack was live-streamed on a gaming platform.
Out of the 13 victims, 11 are African Americans while two are white, according to Buffalo Police Commissioner Joseph Gramaglia.
U.S. Secretary of Homeland Security Alejandro Mayorkas has been briefed on the shooting, according to an official tweet from the department.
"DHS (the Department of Homeland Security) is actively coordinating with all relevant local, state, and federal agencies and will continue to provide the Department's full support," the tweet read.
The White House has also reacted to the incident, calling it a "horrific shooting."
U.S. President Joe Biden "will continue to receive updates throughout the evening and tomorrow as further information develops," according to a statement from White House press secretary Karine Jean-Pierre.
"The President and the First Lady are praying for those who have been lost and for their loved ones," Jean-Pierre added.