The president of the national Fraternal Order of Police, the country's largest police organization, on Tuesday asked Wal-Mart to stop selling t-shirts and sweatshirts which say "Black Lives Matter" and "Bulletproof" on the department store's website. On Tuesday night, Wal-Mart said it would remove the shirts which say "Bulletproof," but not the "Black Lives Matter" shirts.

"Black Lives Matter" is a slogan and protest movement which emerged after the death of Trayvon Martin in 2012 and police-involved slayings in 2014, and is seen as offensive by many in law enforcement. The website Breitbart.com posted an article last week which said that Wal-Mart was "selling Black Lives Matter clothing and other items," though the merchandise is actually being sold through Wal-Mart's website by Old Glory Merchandise, a music and entertainment apparel dealer out of Connecticut.

Chuck Canterbury, the FOP president, wrote to Wal-Mart CEO C. Douglas McMillon Tuesday to advise him that the Wal-Mart website was selling "offensive shirts and sweatshirts," and "I urge you to prohibit the use of the Wal-Mart name and website for the retail sale of these products." The Wal-Mart site and Old Glory's site also sell "Blue Lives Matter" shirts.

Canterbury said he understood that a third party was selling the merchandise, but "I am concerned that allowing these articles to be sold in this way will damage your company's good name amongst FOP members and other active and retired law enforcement officers." Canterbury added, "Commercializing our differences will not help our local police and communities to build greater trust and respect for one another."

Wal-Mart issued a statement Tuesday night saying that, "Like other online retailers, we have a marketplace with millions of items offered by third parties that includes Blue Lives Matter, Black Lives Matter and All Lives Matter merchandise. After hearing concerns from customers, we are removing the specific item with the 'bulletproof' reference." The "bulletproof" shirts say "Bulletproof" with "Black Lives Matter" beneath that line.

Old Glory did not immediately respond to requests for comment.

Jim Pasco, the executive director of the police union in Washington, said the issue was raised by union members who felt Wal-Mart was selling anti-police items. "There are a lot of people who feel too many guns are sold," Pasco said. "Why not speak out against things that might be seen as fomenting violence, rather than things that commit violence?"