Amazon has blamed a "bad actor" for racist abuse that appeared on multiple listings on its UK website.
The abuse, now removed, appeared when users searched the online shop for Apple AirPods and similar products.
It was unclear how long the racist language remained on the site, but it sparked outrage on Twitter and the sharing of screenshots and video grabs.
"We investigated, removed the images in question and took action against the bad actor," Amazon told the BBC.
The company did not elaborate on the "bad actor", nor give details of how many products were defaced and how long the abuse was visible on the listings.
Nadine White, a journalist for the Huffington Post, tweeted that the abuse "needs to be acknowledged, removed, explained, apologised for asap. Being Black right now is hard enough; we don't need to be called the N- word while shopping online, to boot".
Another Twitter user said Amazon should have been able to remove the offending messages in minutes. "They're still on Amazon UK. Extraordinarily poor site administration," he said during early hours of Sunday.
Amazon also allows third-party retailers to sell goods through its website, with the company making about half its retail revenues from this.
But the Amazon Marketplace platform has come under scrutiny.
There has been concern about counterfeit goods appearing in the listings, and during the coronavirus pandemic Amazon was criticised for not doing enough to stop sellers inflating prices.
In April, five Amazon e-commerce websites, including the UK, were added to the US trade regulator's "notorious markets" report on marketplaces known for counterfeiting and piracy concerns.
Amazon disagreed strongly with the move, saying in a statement that "this purely political act is another example of the administration using the US government to advance a personal vendetta against Amazon".