By Alana Wise, Luciana Lopez and Edward McAllisterCHARLESTON, S.C. (Reuters) - South Carolina activists on Monday stepped up their call for lawmakers to remove the Confederate battle flag from the grounds of the state capitol, five days after a white gunman allegedly shot dead nine black worshippers at a historic church in Charleston.The demand by U.S. civil rights leaders and local elected officials for the state to remove the rallying symbol of the pro-slavery South during the U.S. civil war follows revelations that the 21-year-old white man, charged with Wednesday's attack on the Emanuel African Methodist Church, had posted a racist manifesto on the internet.Local clergy had set a Monday press conference to call for a rally on Tuesday at the statehouse to demand the removal of the flag, which many liberal Americans consider an emblem of slavery, but which many conservatives say is a symbol of the south's history and culture.The suspect, Dylann Roof, was arrested on Thursday and charged with nine counts of murder for gunning down members of a Bible study group at the church nicknamed "Mother Emanuel" after sitting with them for an hour on Wednesday night.The attack, in a year in which the United States has been rocked by protests over police killings of unarmed black men, has inflamed a national debate on race relations, policing and the criminal justice system.President Barack Obama weighed in on the issue in a podcast posted online on Monday, saying the killings showed that the United States still had a long way to go in addressing racism, using an epithet to make his point."We're not cured of it," Obama told Mark Maron, host of the "WTF" podcast. "And it's not just a matter of it not being polite to say 'nigger' in public. That's not the measure of whether racism still exists."South Carolina Governor Nikki Haley, a Republican, was set to make remarks in her office in the state capital of Columbia at 4:00 p.m. ET (2000 GMT). Her office did not immediately disclose the topic of her remarks.Hundreds of people on Sunday packed the "Mother Emanuel" church for a memorial service to the dead, who included four pastors.(Writing by Scott Malone; Editing by Bernadette Baum)Join the conversation about this story Click here to read full news..