The Charleston, South Carolina church shooting on Wednesday that resulted in the death of nine people, including State Senator and Pastor Clementa Pinckney, has reignited the issue of bearing guns in the United States.

Charles Cotton, a director of the National Rifle Association (NRA), which strongly lobbies for gun rights, blamed Pinckney for the killing.

"And he voted against concealed-carry. Eight of his church members who might be alive if he had expressly allowed members to carry handguns in church are dead. Innocent people died because of his position on a political issue," posted Cotton on TexasCHLForum.com, which has since been deleted.

On the opposite side of the issue, President Barack Obama called for more gun control during remarks at the US Conference of Mayors on Friday.

"I refuse to act as if this is the new normal, or to pretend that it's simply sufficient to grieve and that any mention about us doing something to stop it is somehow politicising the problem," Obama said, referring to the church massacre in Charleston, South Carolina.

Obama's call is supported by a new study that showed that "guns are rarely used to kill criminals or stop crimes."

"In 2012, for every justifiable homicide in the United States involving a gun, guns were used in 32 criminal homicides. And this ratio, of course, does not take into account the tens of thousands of lives ended in gun suicides or unintentional shootings that year," according to the June 2015 "Firearm Justifiable Homicides and Non-Fatal Self-Defense Gun Use" study by the Violence Policy Center, which advocates gun control.

A Washington Post story said based on FBI data, for every "justifiable" gun homicide in 2012, there were 34 criminal gun homicides. Justifiable homicide, the FBI said, is the killing of a felon, during the commission of a felony, by a private citizen.

Last December, after the killing of 26 people including 20 children at the Sandy Hook Elementary School in Newtown, Connecticut, NRA Executive Vice President Wayne LaPierre said the victims might still be alive if school personnel had guns.

"The only way to stop a bad guy with a gun is with a good guy with a gun," said LaPierre, according to CBS.

But in his speech at the US Conference of Mayors on Friday, President Barack Obama noted that more than 11,000 Americans were killed by gun violence in 2013. He said if Congress had passed a common-sense gun safety reforms after the Newtown and Charleston incidents, "we might still have some more Americans with us" although he cautioned that no reform can guarantee the elimination of violence.

"You don't see murder on this kind of scale, with this kind of frequency, in any other advanced nation on Earth. What's different is not every country is awash with easily accessible guns," he said.

Obama also pointed out that racial bigotry was what motivated suspect Dylann Roof to kill the victims.

"The apparent motivations of the shooter remind us that racism remains a blight that we have to combat together," he said. "We have made great progress, but we have to be vigilant because it still lingers. And when it's poisoning the minds of young people, it betrays our ideals and tears our democracy apart."