In a letter appearing online Thursday, Facebook CEO Mark Zuckerberg and his wife Priscilla Chan write that President Trump’s “divisive and incendiary rhetoric” has left them “deeply shaken and disgusted” in a volatile time that they say requires “unity” in the U.S.

Writing under the letterhead of their Chan Zuckerberg Initiative, which focuses on technology solutions to social problems, the couple were responding to last week’s call by more than 270 scientists that Facebook address what the scientists described as “misinformation” appearing on social media.

A copy of the Chan-Zuckerberg letter was posted on Twitter by Recode journalist Teddy Schleifer.


The scientists, many of them funded by the initiative, accused President Trump of being a source of the misinformation.

“Social media platforms, like Facebook, have emerged as primary ways of communicating information,” the scientists wrote to Zuckerberg last Saturday. “While they have allowed dissemination of information across the globe, they also facilitate the spread of misinformation. The spread of news that is not vetted for factual accuracy leads to confusion and a mistrust of experts.”

Later, the scientists wrote, “(W)e were disconcerted to see that Facebook has not followed their own policies in regards to President Trump, who has used the Facebook platform to spread both misinformation and incendiary statements. For example, his statement ‘when the looting starts, the shooting starts” is a clear statement of inciting violence.”

The scientists – who were referring to a May 29 Trump message that was flagged by Twitter but not by Facebook -- then called upon Facebook “to consider stricter policies on misinformation and incendiary language that harms people or groups of people, especially in our current climate that is grappling with racial injustice.”

Trump later denied a Twitter claim that the tweet was "glorifying violence."

“Looting leads to shooting, and that’s why a man was shot and killed in Minneapolis on Wednesday night - or look at what just happened in Louisville with 7 people shot,” Trump tweeted Friday. “I don’t want this to happen, and that’s what the expression put out last night means. It was spoken as a fact, not as a statement.”

In their response to the scientists, Zuckerberg and Chan write that they, too, were bothered by Trump’s message.

“(W)e are deeply shaken and disgusted by President Trump’s divisive and incendiary rhetoric at a time when our nation so desperately needs unity,” they write. “This is an extraordinarily painful inflection point in our nation’s story, particularly for the Black community and our Black colleagues, who have lived with the impacts of systemic racism for generations.”

But they also note, referring to a Zuckerberg post from last Friday, that Facebook is disinclined to censor messages unless the content “is actually inciting violence.”

The couple go on to say that they and other leaders at the initiative and at Facebook were committed to helping “advance racial justice” through steps that include considering “a diversity of perspectives, viewpoints and lived experiences.”


Separately on Thursday, Facebook issued a sharp response to Joe Biden, after the presumptive Democratic presidential nominee called on the company to remove “false, viral information,” and prevent candidates and political-action committees from spreading “lies” online.

In its response to Biden, Facebook noted that President Trump recently issued an executive order preventing social media companies from fact-checking political statements.

"Just as they have done with broadcast networks – where the US government prohibits rejecting politicians’ campaign ads – the people’s elected representatives should set the rules, and we will follow them. There is an election coming in November and we will protect political speech, even when we strongly disagree with it," the Facebook statement said.


Fox News' Brie Stimson and Christopher Carbone contributed to this story.