The Facebook logo at an innovation hub in Berlin, Germany.
The Facebook logo at an innovation hub in Berlin, Germany.Sean Gallup/Getty Images

A news site was able to target ads at Facebook users who expressed interest in “Jew hater” and “how to burn Jews.”

ProPublica, an investigative site, reported Thursday that Facebook’s advertisement algorithms generated categories including “Jew hater,” “How to burn Jews,” and “History of ‘why Jews ruin the world.’”

Facebook removed the categories after being alerted to their existence and said it would seek to prevent such categories from popping up for potential advertisers.

The categories on their own were too small to justify an ad buy, according to the Facebook system, so ProPublica added as targets the SS and the Nazi Party, available on Facebook’s generated list as “employers,” and the National Democratic Party of Germany, a current far right political party in Germany.

ProPublica paid $30 for three targeted posts, which reached 5,897 people.

In advising ProPublica on whom to add in order to reach enough users to justify an ad, Facebook’s automated system recommended “Second Amendment,” apparently correlating gun rights advocates with anti-Semites.

Facebook has been used in the past to encourage terror attacks against Israelis, prompting Israeli security officials to press Facebook to crack down on incitement to violence.