Federal regulators have accused Facebook of allowing landlords and real estate brokers to engage in housing discrimination. A formal complaint filed against the social media company says that it allows the use of targeted Facebook ads to discriminate on the basis of race, sex, religion, disability and other characteristics. In response, Facebook said that it does not allow discrimination.

The Department of Housing and Urban Development is accusing Facebook of violating the Fair Housing Act. Anna María Farías, HUD’s assistant secretary for fair housing and equal opportunity, released a statement saying, “The Fair Housing Act prohibits housing discrimination. When Facebook uses the vast amount of personal data it collects to help advertisers to discriminate, it’s the same as slamming the door in someone’s face.” According to the HUD complaint, the alleged violations occurred as recently as last month.

The HUD filing bolsters the arguments made in a lawsuit brought against Facebook by advocacy groups last spring. The case, filed in March in New York City by the National Fair Housing Alliance, claims that Facebook’s advertising tools systems allow people placing real estate ads to exclude certain audiences, such as women and families with children. Diane L. Houk, one of the attorneys on that case, said that the new complaint was “a very important step by HUD to enforce the Fair Housing Act.”

Facebook has argued that it is protected from the federal housing law by the Communications Decency Act, which limits the liability of website operators. The government countered that Facebook should be classified as an internet content provider in this case, which would make the company subject to the Fair Housing Act.

These types of allegations have been swirling since ProPublica published an expose on the housing ads in 2016. The reporters working on that story stated that they were able to post ads that were not to be shown to anyone with what Facebook’s ad tool calls an “ethnic affinity” of African-American, Asian-American or Hispanic. In 2017, ProPublica reported that it bought dozens of home rental advertisements on Facebook that specifically excluded “African Americans, mothers of high school kids, people interested in wheelchair ramps, Jews, expats from Argentina and Spanish speakers” as part of the intended audience.