The gunman accused of carrying out a racially-motivated mass shooting at a Buffalo, New York grocery store had sought to drive through the city to kill additional Black people, law enforcement said on Monday.

Payton Gendron, the alleged gunman, told police he wanted "to drive out of here and continue driving down Jefferson Ave. looking to 'shoot more Black people,' as he put it, and possibly even going to another store location," Buffalo Police Commissioner Joseph Gramaglia told ABC News.

Saturday's mass shooting left 10 people dead at Tops Friendly Market. Three other victims were injured.

Law enforcement is investigating the shooting as a racially-motivated hate crime, and potentially an act of domestic terrorism.

"This is an absolute racist hate crime. This is someone who has hate in their heart, soul and mind," Gramaglia told a press conference.

Police have said Gendron was motivated by a white supremacist conspiracy theory known as replacement theory, which has been at the heart of several other hate crime attacks.

Its adherents falsely believe there is a goal to diminish the influence of whites in societies through non-white immigration to countries traditionally dominated by whites, and by ensuring whites having lower birth rates than non-whites.

The gunman behind the 2019 shooting in El Paso, Texas that targeted Latinos touted the conspiracy theory, as did the gunman who targeted a Pittsburgh, Pennsylvania synagogue the year prior.

The conspiracy theory was echoed during the far-right 2017 Charlottesville, Virginia hate rally in which participants variously shouted “You will not replace us!,” and “Jews will not replace us!”

Police said Gendron drove some 200 miles from his hometown of Conklin, New York to perpetrate the apparent hate crime in Buffalo on Saturday. Authorities are continuing to examine a 180-page manifesto purportedly posted online by the suspect prior to the attack.

Gendron's attorney has pleaded not guilty on his client's behalf./aa ​​​​​​