A Confederate battle flag flies at the grave of L.S. Axson, a soldier in the Confederate States Army in the US Civil War, in Magnolia Cemetery in Charleston, South Carolina June 22, 2015. [Photo/Agencies]

CHARLESTON/COLUMBIA, S.C. - South Carolina Governor Nikki Haley on Monday called on lawmakers to take down the Confederate battle flag at the state capitol grounds, a week after a white gunman allegedly shot dead nine black worshipers at a historic church.

The flag that has flown at the State House grounds in Columbia for a half century became a fresh focus of criticism after the Charleston church massacre. Federal authorities are investigating the attack as a hate crime and an act of terrorism by accused gunman Dylann Roof, 21, who posed with the flag in photos posted online.

"It's time to move the flag from the capitol grounds," Haley, a Republican, told a news conference in the state capital, about 100 miles (161 km) from the shooting.

"The flag, while an integral part of our past, does not represent the future of our great state."

Haley called on lawmakers, whose normal legislative year wraps up this week, to address the issue over the summer and said she would order a special session if they did not.

The shooting at Emanuel African Methodist Episcopal Church came in a year of intense debate over US race relations following the killings of unarmed black men by police officers, which has sparked a reinvigorated civil rights movement under the "Black Lives Matter" banner.

Opponents of flying the flag at the State House grounds consider it an emblem of slavery that has become a rallying symbol for racism and xenophobia in the United States.

Supporters, who fly the flag at their homes, wear it on clothing and put it on bumper stickers, see it as a symbol of the South's history and culture, as well a memorial to the roughly 480,000 Confederate casualties during the 1861-65 Civil War. That figure includes the dead, wounded and prisoners.