The incident occurred at 9pm last night when a white male opened fire in the Emanuel African Methodist Episcopal Church in downtown Charlestown.
Local media reports that pastor and South Carolina State Senator, Clementa Pickney, is among the dead, but police officials have not yet released the names of the victims,
Commenting on the devastating incident, Mayor Reilly said: "This is the most unspeakable and heartbreaking tragedy. People in prayer, coming together, praying and worshiping God, to have an awful person come in and shoot them is inexplicable, obviously the most intolerable and unbelievable act possible."
The church, in which the shooting occurred, is believed to be one of the oldest black churches in the US, having been built in 1891.
Speaking out in the aftermath of the tragedy, police chief Greg Mullen said the police believe it was a hate crime and confirmed that authorities are searching for a 21-year-old white male in connection with the incident.
Paying tribute to the victim and their families, Governor Nikki R. Haley said: "While we do not yet know all of the details, we do know that we’ll never understand what motivates anyone to enter one of our places of worship and take the life of another. Please join us in lifting up the victims and their families with our love and prayers."
Mourners have gathered in the vicinity of the church to pay respect to the victims.
