Police captured the white suspect Thursday in a gun massacre at one of the oldest black churches in the United States, the latest deadly assault to feed simmering racial tensions.

Police detained 21-year-old Dylann Roof, shown wearing the flags of defunct white supremacist regimes in pictures taken from social media, after nine churchgoers were shot dead during bible study on Wednesday.

He was caught at a traffic stop in North Carolina and brought back to Charleston, South Carolina, the scene of the slaughter in the Emanuel African Methodist Episcopal Church.

The carnage was the worst at a US place of worship in decades and recalled the darkest periods of US history, in a church once burned to the ground after a failed slave revolt.

Charleston Police Chief Gregory Mullen said: "I do believe it was a hate crime."

Booking photos released by Charleston County jail showed a sullen, boyish suspect with a pudding-bowl haircut.

A reported friend of the accused, 21-year-old Dalton Tyler, told ABC News that Roof had spoken in support of racial segregation and had "said he wanted to start a civil war."

In Washington, a clearly frustrated President Barack Obama said the "senseless murders" showed the United States will have to come to grips with its gun culture.

"At some point, we as a country will have to reckon with the fact that this type of mass violence does not happen in other advanced countries," Obama said at the White House.


'Broken'


Members of the historic church's mainly black congregation, many of them elderly, gathered Wednesday evening for a Bible study meeting.

The shooter walked into the building, sat for about an hour, then opened fire, Mullen said.

Sylvia Johnson, a relative of one of the victims, told MSNBC news a survivor had told her that the gunman had made a racist rant and reloaded five times during the attack.

"He said: 'You rape our women and you're taking over our country and you have to go,'" she told the network.

Three men and six women were killed, and more people were wounded. Among the dead was the church's pastor, 41-year-old Clementa Pinckney, also a Democratic state senator.

The other victims were identified in reports as librarian Cynthia Hurd, 54; high-school track coach Reverend Sharonda Coleman-Singleton, 45; barber Tywanza Sanders, 26; church worker Ethel Lance, 70; church member Susie Jackson, 87; Reverend DePayne Middleton, 49; vicar's wife Myra Thompson, 59; and Reverend Daniel Simmons, 74.

"The heart and soul of South Carolina was broken," a tearful state Governor Nikki Haley said.

Hate crimes probe


Detectives and FBI agents headed to Shelby, a four-hour drive away in North Carolina -- where Roof was apprehended during a traffic stop -- to interview the suspect and gather evidence.

FBI Special Agent John Strong said agents were investigating whether a federal hate crime had taken place and were cooperating with local and state law enforcement.

"The suspect is in custody," he said. "The immediate threat to the community no longer exists and we'll let the legal process run its course. There are no longer any lives at risk."

The shooting came at a time of heightened tension in America, after several high-profile killings of unarmed black men at the hands of white police triggered protests and a national debate on race.

A picture on Roof's Facebook page showed him wearing a jacket emblazoned with the flags of apartheid-era South African and former white minority-ruled Rhodesia, now Zimbabwe.

He is also pictured with a car with a license plate referring to the "Confederate States of America," the secessionist slave-owning south defeated in the US Civil War.


'Slave revolt'


The Atlantic coast city of Charleston is known locally as "The Holy City," due to its large number of churches, many of them community anchors for a diverse range of ethnic groups.

"In this great country, we hold sacred the places where people come and practice their faiths in safety and in peace," Mayor Joseph Riley said.

Dot Scott of the local chapter of the National Association for the Advancement of Colored People said the shooter may not have drawn attention because the church is a tourist draw.

"It's not out of the ordinary that folks just walk into the sanctuary and sit and listen to what's going on," Scott told CNN.

The Emanuel African Methodist Episcopal Church is the oldest such church in America's southern states.

It was founded in 1816 and in 1822 was investigated for its involvement with an unsuccessful planned slave revolt.

The shooting is the latest in a long list of mass shootings in the United States.

The deadliest in recent years include the April 2007 Virginia Tech shooting, when 32 were killed, and the December 2012 Sandy Hook elementary school shootings in Newtown, Connecticut, when a total of 27 people died, including 20 children.

In August 2012, six people were shot dead at a Sikh temple in Wisconsin by a neo-Nazi.