A 21-year-old white man confessed to shooting dead nine black people at a historic South Carolina church, and hoped his actions would start a race war in the United States, CNN reported on Friday, citing unnamed law enforcement officials.
Charleston Police spokesman Charles Francis declined to comment on the reports of a confession.
Dylann Roof is due to face a bail hearing later on Friday, where he will appear by video link from the Charleston-area detention center, to which he was brought by police following his arrest in North Carolina, 220 miles (354 km) north of the nearly 200-year-old Emanuel African Methodist Episcopal Church.
U.S. officials are investigating Roof's attack, in which four ministers were killed including a Democratic state senator, as a hate crime. It comes in a year of turmoil in the United States, where police killings of several unarmed black men has provoked angry national debates about race relations, policing and the criminal justice system.
Roof had intended to set off new racial confrontations with his attack, CNN reported, citing a law enforcement source. The report could not be immediately confirmed.
South Carolina Governor Nikki Haley told NBC's "Today" show on Friday that she would prefer to see Roof tried on state charges and believed state prosecutors should pursue a death sentence.
"This is an absolute hate crime," Haley said. "We've been talking with the investigators because we've been going through the interviews, they said they looked pure evil in the eye."
South Carolina is one of just five U.S. states that does not have a hate crime law, which typically imposes additional penalties on crimes committed because of a victim's race, gender or sexual orientation.
President Barack Obama said Thursday the attack stirred up "a dark part" of U.S. history and illustrated the continuing dangers of the nation's liberal gun laws, which gun-rights supporters say are protected by the Second Amendment of the U.S. Constitution.
The church, known as "Mother Emanuel," was founded in the early 19th century by black worshippers who were limited in how they could practice their faith at white-dominated churches. Burned to the ground in the late 1820s when one of its founders drafted plans for a slave revolt, the church was later rebuilt.
Compounding anger over the incident, the South Carolina capital continues to fly the Confederate battle flag, that was the symbol of the pro-slavery South during the U.S. Civil War.
In addition to the church's leader and Democratic state Senator Clementa Pinckney, other victims included three pastors - DePayne Middleton Doctor, 49; Sharonda Coleman Singleton, 45; and Reverend Daniel Simmons, 74.
Also killed were Cynthia Hurd, 54, a public library employee; Susie Jackson, 87; Ethel Lance, 70; Tywanza Sanders, 26; and Myra Thompson 59, an associate pastor at the church, according to the county coroner.
Area residents, including a group of nuns, filed past the historic church early Friday that was the site of Wednesday's shooting. Many tearfully offered prayers and left flowers near the line of yellow police tape, behind which law enforcement agents continued to gather evidence.