If you pay any attention to Facebook’s trending news content, you’ve probably seen more than a few phony stories pop up in your feed. That has been especially true this election season, with both right-wing and left-wing blogs circulating false articles and attacks on their political opponents — and with Facebook’s recent lack of human editors, these stories often enter the Trending Stories rotation. Now the President of the United States himself has weighed in on the issue, calling out Facebook for publishing fake news and warning users to be skeptical of these hoax stories around the election.

“The way campaigns have unfolded, we just start accepting crazy stuff as normal and people if they just repeat attacks enough and outright lies over and over again,” President Obama said at a recent rally in Ann Arbor, Michigan. “As long as it’s on Facebook, and people can see it, as long as it’s on social media, people start believing it, and it creates this dust cloud of nonsense.”

Indeed, a recent BuzzFeed News analysis of six so-called “hyperpartisan” sites found that right-wing sites published false or misleading information 38 percent of the time during the course of the study, while left-wing sites did so in about 20 percent of posts.

As always, don’t believe everything you read on Facebook — especially if it involves politics or the election.