Facebook has said it will stop running all political and social-issue adverts after polls close in the US presidential election on 3 November.
It said the temporary measure would “reduce opportunities for confusion or abuse” ahead of results.
Facebook has already banned ads that prematurely declare victory in the election.
But one digital-rights campaign group said the change “isn’t going to fix the problem at all”.
Fight For The Future said misinformation was often spread through Facebook Groups, which are promoted by the social-network’s algorithms.
On Tuesday, Facebook announced it would remove any Pages, Groups or Instagram accounts representing a conspiracy theory known as QAnon.
But the social network has been criticised for deciding not to fact-check posts by politicians.
In a blog post, it said it would label politicians’ posts, if a candidate or party “declares premature victory before a race is called by major media outlets”.
It will also display notifications directing users to its own voting-information page.
Democrat senator Elizabeth Warren, who is often critical of Facebook, said the social network had made “performative changes”.
“The problem isn’t the ads themselves,” she said.
“The problem is Facebook’s refusal to regulate its ads, change its broken algorithm, or take responsibility for the power it’s amassed.”
Rival social networks, including TikTok and Twitter, do not allow paid political ads.