{blackbabes} Serena's sadness at Charleston massacre

London (AFP) - US tennis star Serena Williams called the Charleston massacre unspeakably sad and recalled Monday how she refused to play in South Carolina while the Confederate flag flew above the state legislature.

A black female protester scaled a flagpole on the grounds of the South Carolina legislature in Columbia on Saturday and removed the Confederate flag amid fierce debate about the racially-charged symbol in the wake of the Charleston killings elsewhere in the US state.

Impassioned debate about the flag was sparked by the mass shooting of nine black worshippers in Charleston on June 17. The alleged white supremacist gunman, Dylann Roof, 21, appeared in photos online with the flag.

In 2000, Williams pulled out of the Family Circle Cup in South Carolina in support of the National Association for the Advancement of Colored People's call for a boycott over the Confederate flag flying above the state legislature.

The flag was eventually removed from the state house dome to a monument in the grounds later that year.

"I wouldn't go to Charleston until the flag was removed. Once it was, I went there, and only after the Confederate flag was removed," Williams said after winning her first round match at Wimbledon.

"What happened in Charleston is a tragedy yet again to our country, the United States. It's really unspeakable how sad it is and how much of a toll it can have.

"But you just have to continue to have faith, continue to believe, continue to be positive, continue to help people to the best of your ability."

There has been a growing clamour for the flag -- branded by US President Barack Obama as "a reminder of systemic oppression and racial subjugation" -- to be removed from the grounds of the state house in Columbia.

Once flown by the rebel army of the slave-owning South during the Civil War, the confederate flag is seen by some as a symbol of regional heritage. But many more view it as an ugly reminder of racism's cruel legacy.

Williams said she was proud of how the community reacted to the Charleston massacre.

"Everyone was so positive and a lot of people went there. Obviously Obama. It was a very emotional time for many people of all races in the United States, and outside the United States," she said.