NEW YORK - An avowed white supremacist pleaded guilty on Monday to first-degree murder and other state charges in a mass shooting that killed 10 people at a supermarket in May, local media reported.

At a hearing in Erie County Court, Payton Gendron, 19, pleaded guilty to 25 counts related to the shooting, which took place in a predominantly black neighbourhood in Buffalo, New York.

In June, he initially pleaded not guilty after a grand jury returned an indictment.

Gendron, from Conklin, New York, was charged with 10 counts of first-degree murder and 10 counts of second-degree murder, all of them considered hate crimes. The shooting also left three people wounded.

The grand jury indictment, which included a charge of domestic terrorism motivated by hate, accused Gendron of carrying out the attack based on the perceived race of his victims.

He faces a sentence of life in prison without parole. New York does not have a death penalty.

Gendron, who was 18 at the time of the shooting, drove three hours from his home near Binghamton, New York, to the Tops Friendly Markets store in Buffalo, the authorities said.

He was looking for a public location in an area where many black people lived.

At the supermarket, he shot 13 people with a semi-automatic, assault-style rifle. Eleven of the victims were black.

Police say he left a racist manifesto online before the attack and live-streamed the shooting on social media.

Mr Terrence Connors, an attorney for relatives of seven of the dead and two surviving victims, said earlier that Gendron had no plea agreement with prosecutors.

A sentencing hearing is expected at a later date.

A separate indictment returned in the US District Court in July charged Gendron with 27 federal hate crimes and firearms offences, for which he could face the death penalty if convicted. AFP