Facebook has announced that it will not take on any new political ads in the seven days prior to the US election on 3 November.
He said that he was "worried" about divisions in the country potentially leading to civil unrest.
He added that Facebook would also label posts from candidates attempting to declare victory before the votes had been counted.
The social network has faced criticism for allowing political ads to be "micro-targeted" on its platform so that they are only seen by small communities rather than debated more widely in the days after they appear.
The new steps could serve as a precedent for how the firm handles elections elsewhere in the future.
"This election is not going to be business as usual," Mr Zuckerberg wrote.
"With our nation so divided and election results potentially taking days or even weeks to be finalised, there could be an increased risk of civil unrest across the country," he added.
- no new political ads will be accepted in the week before the election
- posts claiming people will get Covid-19 if they take part in the vote will be removed
- information labels will be attached to posts seeking to delegitimise the outcome of the election
- labels will also be added to posts by candidates that seek to claim victory before the final results are in
Mr Zuckerberg also said that Facebook had also "strengthened" its enforcement policies against movements known to spread conspiracy theories, such as QAnon.
Thousands of Facebook groups associated with these movements had already been removed, he said.