The Ku Klux Klan plans to hold a pro-Confederate flag rally at the South Carolina Capitol, where a man was arrested on Monday night in a confrontation with anti-flag protesters over a symbol associated with slavery.

The Civil War-era flag has emerged as a flashpoint after a shooting that killed nine people at a historic black church in Charleston, South Carolina, during a Bible study session.

The suspected shooter, Dylann Roof, 21, who is white, had posed with a Confederate flag in photos posted on a website that also displayed a racist manifesto attributed to him.