PHILADELPHIA — The leader of a Black Lives Matter demonstration here admonished white activists joining the march to the Democratic National Convention, warning that they will lose out when the movement succeeds in ending America’s “white supremacy” system.

The leader of the march, who described himself as a Mexican immigrant with Native American heritage, looked out from the back of a pickup truck and surveyed the predominately white crowd of protestors.

He said he had a message for the white supporters of Black Lives Matter.

“White supremacy — that’s a system you benefited from and you’re no longer going to benefit from it,” he blared through a bullhorn.

He said that the white followers should stop and think about that if they truly wanted to promote the movement.

The crowd fell silent.

They quickly returned to cheers and chants as the leader redirected his attacks on police, the convention and Democratic presidential nominee Hillary Clinton.

Later, the several hundred protestors marched across the city to the convention at Wells Fargo Center.