Editor’s note: This article contains descriptions of imagery depicting child sexual abuse. Reader discretion is strongly advised.

Over the last nine months, Mark Zuckerberg’s Meta has run dozens of paid ads that include explicit AI-generated child sexual abuse material (CSAM) and images of minors alongside sexually suggestive statements, according to details of the ads shared with WIRED. The ads, which in some cases reached several thousand accounts, were targeted at people living in the United States, United Kingdom, and more than a dozen European countries.

More than 50 image and video ads containing abusive content were recently discovered in Meta’s ad library by researchers at the Tech Transparency Project (TTP), with the listings showing that some ads linked out to so-called nudify or undressing apps. Meta’s ad library—a transparency tool that catalogues ads displayed on the company’s platforms—shows the ads running across Facebook, Instagram, Messenger, and/or Threads. The findings are the second time in recent weeks that paid ads linked to child sexual abuse material have been found on Meta’s platforms.

“These ads made no effort to mask the images or hide what they were promoting,” Katie Paul, the director of the TTP, an independent watchdog group, tells WIRED. “It’s important to point out that this isn’t content posted by third parties on Facebook or Instagram, these are ads that were reviewed, approved, and allowed to run by Meta, never encountering interference while the company collected the ad dollars.”

The ads discovered by the researchers—which have now been removed by Meta for violating its policies on child sexual abuse and exploitation material, and adult sexual solicitation and nudity—were all published between November last year and the start of August. The ads, according to data in Meta’s ad transparency library, often ran over a period of several days and some only targeted men.

One video ad, the TTP researchers say, used a thumbnail image of a child sitting on the floor with text appearing on top of it saying: “Realizing Deep Fantasies with Generation AI [sic]. There is so much more than what is shown, use your imagination.” The researchers say that when the ad was clicked, it played video clips of adults involved in sexual acts and then added the child’s face from the thumbnail to a sex act.

Another ad the researchers say had been repeatedly posted showed an image of a young girl laying back with her legs spread in a sexual position with text above it saying: “I can show you more.”

Most of the ads were not actively being shown to users when researchers found them, but they continued to be available, apparently undetected, in Meta’s ad library for months. Although many of the ads, according to Meta’s data, only “reached” a handful of accounts, at least one reached 2,563 accounts in Europe—including in France, Germany, Ireland, Italy, the Netherlands, Spain, Sweden, and the United Kingdom. Meta’s ad library database does not include details about ad performance in the US or all countries, so the overall reach may be higher.

Paul says TTP first discovered the ads last week as its researchers continued to investigate nudify app ads on Meta, after publishing a report about a Chinese advertising partner posting them. Paul says the organization immediately reported the findings to National Center for Missing and Exploited Children’s CyberTipline, which allows people to report online child sexual abuse material. A NCMEC spokesperson says it does not comment on reports it receives.

After WIRED reached out to Meta, the company removed the ads from its advertising library. “Sexual exploitation is horrific, and we work aggressively to keep it off our platform,” a Meta spokesperson says. “The majority of these ads had minimal reach and many were disabled before WIRED shared them. Many of these ads also predate new AI technology we launched recently to better detect and block violating ads at upload—and we’re constantly improving these systems. From removing over 36 million pieces of child sexual exploitation content last year to taking legal action against nudify app developers, we will continue to relentlessly fight this abuse.”