Prominent U.S. flag makers said on Tuesday they will stop manufacturing and selling Confederate battle flags after last week's attack on worshippers at a black church in Charleston, South Carolina.

Reggie VandenBosch, vice president of sales at privately owned Valley Forge Flag, said the Pennsylvania-based company came to the decision as pressure grew on South Carolina to remove the banner from outside the State House in Columbia.

Annin Flagmakers, based in Roseland, New Jersey, announced that it too would stop making the flag used by the pro-slavery Confederate states during the 1861-65 American Civil War.

Eder Flag Manufacturing, based in Wisconsin, also said it would no longer sell or manufacture Confederate flags because of the Charleston shooting.

While some in South Carolina see the flag as a reminder of the state's proud history of defying federal authority, many others view it as a shameful tribute to the institution of slavery, once a pillar of the U.S. South's plantation economy.

"We hope that this decision will show our support for those affected by the recent events in Charleston and, in some small way, help to foster racial unity and tolerance in our country," Valley Forge Flag said in a statement.

The 133-year-old company sells millions of flags each year, VandenBosch said, with Confederate flags making up only a tiny slice of that business.

Annin makes some 10 million flags every year, and only about 1,000 of them are Confederate flags, said Mary Repke, the company's vice president of marketing.

The flags are popular in Civil War re-enactments, she said.

According to Annin's website, the company supplied the U.S. flags for Union troops during the Civil War, and an Annin flag draped the coffin of slain U.S. President Abraham Lincoln.

Supporters say the Confederate flag is a reminder of South Carolina's heritage and a memorial to Southern casualties during the Civil War.

The flag, however, has also long been embraced by white supremacists. Last week, photos emerged online of Dylann Roof, the 21-year-old white man charged with murdering nine black worshippers at the Emanuel African Methodist Episcopal Church in Charleston, posing with the flag.

South Carolina Governor Nikki Haley on Monday called on lawmakers to take down the flag at the state capitol grounds. Wal-Mart Stores Inc (WMT.N) and Sears Holdings Corp (SHLD.O) said they would stop selling products bearing the Confederate flag.

On Tuesday, online auction site eBay Inc (EBAY.O) said it would ban Confederate flags and related items containing the flag's image from its website.

Richard Cohen, president of the Southern Poverty Law Center, which researches U.S. hate groups, applauded the big retailers' decision to pull the merchandise.

"All of the publicity surrounding the sale of Confederate flags became too toxic to handle, and that’s a good thing," he said.