Prayer vigils for the families of those killed at Emmanuel African Methodist Episcopal (AME) Church have been taking place across the US.
The racially-motivated shootings, for which a white man, Dylann Roof, is in custody, have sent shock waves around the country and around the world.
After a prayer meeting at the Second Presbyterian Church next door to Emanuel, Pastor Cress Darwin said: "It was an evil that was incomprehensible. But this community is coming together. Because of it we will be more vigilant in terms of our security. But because of who we serve, we will not stop welcoming in the stranger, because death is not the last word."
One of those praying outside Emanuel, 49-year-old Avis Williamsgrant said a prayer for Roof as well as for the victims' families.
"I'm just thinking that the devil stepped in. And I'm praying for the young man also. We're all God's children and even though he did what he did, he was just a little sick."
A trustee of Emanuel, William Dudley Gregorie, said: "We're not a church that hates. We're a church that's full of forgiveness. We feel that when you hate, you lose, and you let evil in."
Gregorie, who has worshipped at the church all his life and knew all of those killed "like family", continued: "It leaves a void, not just in church, but in our community. But we'll still have to heal. If the sore doesn't heal it just festers and gets worse, and hopefully in time we'll be able to fill this void."
As well as local responses, AME and other churches across the country opened their doors for prayer. Rev Antoni Sinkfield, pastor of Great Bethel AME in Nashville, said: "We are standing in solidarity with our brothers and sisters. There has been a tremendous loss, a heinous act of terror in a place of worship. We are pained by it, and we are grieving the loss."
Pastor Glenn Dames of St James AME Church in Titusville, Florida, which has previously hosted vigils for other shootings, said: "I've been to Emanuel. As a pastor, I know the pain of seeing something like this happen. We believe that in the end, love will conquer hate as difficult as it is to wrap our heads around that right now."
Politicians and public figures also offered what words of comfort they could. President Obama said that it was especially heartbreaking when such tragedies happen "at a place where people are seeking peace", describing the historic church as "a sacred place in the history of Charleston and in the history of America".
He linked the attack to America's liberal gun laws, saying that yet again, innocent people have been killed by someone "who wanted to inflict harm and had no problem attaining a gun". "At some point, we as a country will have to reckon with the fact that this kind of mass violence doesn't happen in other advanced countries," he said.
NACCP President Cornell William Brooks said: "There is no greater coward than a criminal who enters a house of God and slaughters innocent people engaged in the study of scripture. Today I mourn as an AME. minister, as a student and teacher of scripture, as well as a member of the NAACP."
Former Congresswoman Gabrielle Giffords, herself a shooting victim, and Captain Mark Kelly, Co-founders of Americans for Responsible Solutions, said: "Once again, a senseless act of gun violence has brought terror, tragedy and pain to one of our communities. And once again, gunfire and bloodshed has visited one of America's houses of worship."
Democratic Presidential contender Hillary Clinton said: "In the days ahead we will once again ask what led to this terrible tragedy and where we as a nation need to go. In order to make sense of it, we have to be honest. We have to face hard truths about race, violence, guns, and division."
Republican contender Lindsey Graham said: "There are bad people in this world who are motivated by hate. Every decent person has been victimized by the hateful callous disregard for human life shown by the individual who perpetrated these horrible acts. Our sense of security and well-being has been robbed and shaken."