Mark Zuckerberg tells "Axios on HBO" that Facebook is imposing new election rules to deter use of the platform to spread of misinformation and even violence, and to help voters see the results as "legitimate and fair."

Driving the news: The new measures, announced Thursday, include throwing a flag on posts by candidates who claim premature victory, and forbidding new ads within a week of Election Day.

• "There is, unfortunately, I think, a heightened risk of civil unrest in the period between voting and a result being called," Zuckerberg told Axios' Mike Allen.
• "We're trying to make sure that we do our part to make sure that none of this is organized on Facebook."

Between the lines: President Trump has repeatedly suggested that the heavy use of voting by mail this year, driven by the pandemic, could lead to a "rigged election" — despite the long history of voting by mail in the U.S. without fraud.

Zuckerberg said that since the outcome may not be known on election night, Facebook and the media need to start "preparing the American people that there's nothing illegitimate about this election," even if it takes "additional days or even weeks to make sure that all of the votes are counted."

• "So we're going to do a bunch of different messaging around that just to make sure that people know that that's normal."
• "I think we need to be doing everything that we can to reduce the chances of violence or civil unrest in the wake of this election."

Among Facebook's "New Steps to Protect the U.S. Elections":

• "We will attach an informational label to content that seeks to delegitimize the outcome of the election or discuss the legitimacy of voting methods, for example, by claiming that lawful methods of voting will lead to fraud."
• "If any candidate or campaign tries to declare victory before the final results are in, we’ll add a label to their posts directing people to the official results from Reuters and the National Election Pool."

Our thought bubble, from Axios managing editor Scott Rosenberg: If Trump decides to claim victory on the basis of an incomplete election-night count, adding a neutral-sounding "more information" link to his post will hardly make a difference.

The big picture: Facebook was already under pressure to show that it has learned the lessons of the 2016 presidential election. Zuckerberg has acknowledged the platform was caught on its "back foot" in fighting the spread of misinformation.

• Now, experts are worried about the additional danger of voters suspecting fraud — possibly encouraged by social media — if the results aren't called on election night because of the heavier use of mail ballots.

The bottom line: "The country is very charged right now, "Zuckerberg said. "So I think regardless of what we do, there's some chance that this [unrest] happens across the country. I just want to make sure that we do our part to not contribute to it."

Go deeper:

• Facebook will ban new political ads a week before Election Day
• Exclusive: Dem group warns of apparent Trump Election Day landslide