“EBay is currently sweeping our marketplace to remove these items,” a spokeswoman for the company said in an email. New copies of the six books were no longer for sale online at major retailers such as Barnes & Noble on Thursday afternoon, which put eBay among the most prominent platforms for the books to be sold.

Hundreds of listings for the six books could be found on the platform as of Thursday morning, though the number appeared to be lower than it was on Wednesday evening. The eBay spokeswoman said that it would take some time to review seller listings and that the company was monitoring newly published listings.

Retailers frequently make decisions to remove products from their platforms for a variety of reasons. The move made by eBay comes at a time when there is rising concern, especially in conservative quarters, about how major tech platforms decide which content is acceptable. At the same time, others contend the platforms aren’t doing enough to police inappropriate content.