Alphabet Inc.’s Google plans to prohibit fake-news websites from using its ad-selling software, a move that could crimp revenue at those sites.

Google said Monday that it is updating its policies to ban Google ads being placed “on pages that misrepresent, misstate, or conceal information about the publisher, the publisher’s content, or the primary purpose” of the website. The policy would include sites that distribute false news, a Google spokeswoman said.

False news stories, particularly those that spread widely on Facebook Inc.’s social network, became an issue during the recent presidential election. Google experienced its own mishap on Sunday when a false story on a right-wing blog erroneously stating Donald Trump won the popular vote appeared atop some Google search results.

Some media commentators have urged tech companies to try to prevent the spread of such misinformation. Google’s move to block some of such sites’ revenue could prove a significant step in response to the controversy.

Google’s AdSense program, which helps website operators place ads on their sites, is the most popular tool for monetizing websites and helps fund some fake-news sites.