Walmart has agreed to stop selling t-shirts and hooded sweatshirts online that read "Bulletproof. Black Lives Matter."

The national Fraternal Order of Police wrote to the retailer on Tuesday asking it to pull the shirts. Last week, an article on the right-wing web site Breitbart complained that Walmart dropped items that displayed the Confederate flag but still sold the "bulletproof" items.

Walmart (WMT) wasn't actually selling the "Bulletproof. Black Lives Matter." clothes itself, but they were available for purchase on its website via a third-party merchant.

"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," said a Walmart spokesman. "After hearing concerns from customers, we are removing the specific item with the 'bulletproof' reference."

Related: Walmart trims its Christmas Eve hours

Walmart's move satisfied the police union, which does not object to the phrase "Black Lives Matters" by itself, according to James Pasco, the group's executive director.

"The bulletproof thing goes to the new assertiveness of some violence prone individuals to take action directly against police. We find it offensive for that reason," said Pasco.

Pasco added that the police union had yet to reach out to the third party vendor, Old Glory, that sells the bulletproof items. But Old Glory owner Glenn Morelli said he's already decided to take down the shirt from his site as well.

"It wasn't a big seller at all. The Blue Lives Matter sells more than the Black Lives Matter or bulletproof shirts combined," Morelli said. "We don't like to offend anybody."

He said his company offers more than 500,000 different kinds of shirts and sweatshirts on its site.

"When you sell that many, you have to sell all different kinds of shirts," he said. "It's hard to make everybody happy."