Mayor de Blasio is joining hundreds of churchgoers at a rally in support of those killed by a gunman in Charleston, South Carolina.
The march and demonstration were staged by Greater Allen A.M.E. Cathedral of New York in a Queens park.
The rally was held in solidarity with the Emanuel A.M.E. church in Charleston, where nine people were shot to death Wednesday night.
De Blasio denounced the shooting as "an act of racist terrorism."
A state senator led the crowd in chanting that South Carolina should remove the Confederate flag from the grounds of its statehouse.
A track coach and mother who was among the nine people killed in the June 17 shooting was a Newark native.
The alleged gunman, 21-year-old Dylann Roof, is being held in jail, facing nine counts of murder and a weapons charge.
