More than 140 scientists who receive funding from the Chan Zuckerberg Initiative sent a letter to Facebook CEO Mark Zuckerberg on Saturday urging him to better enforce the social media platform’s policies against incendiary language, The Washington Post reported. The Chan Zuckerberg Initiative (CZI) is the philanthropic organization founded by Zuckerberg and his wife Priscilla Chan in 2015, which focuses on using technology to solve social challenges, including criminal justice reform. It is a separate entity from Facebook.

The scientists said in the letter that allowing President Trump to use Facebook “to spread both misinformation and incendiary statements” was not only a violation of Facebook’s policies but “directly antithetical” to CZI’s goal of building a “more inclusive, just and healthy future for everyone.”

“We were disconcerted to see that Facebook has not followed their own policies in regards to President Trump,” the letter states. “For example, his statement ‘when the looting starts, the shooting starts’ is a clear statement of inciting violence.”

The scientists who signed the letter include professors from Stanford, Harvard, and a Nobel laureate, among others.

Zuckerberg said on May 29th that Facebook would not take any action against Trump’s “looting” post, even after Twitter flagged a similar post for “glorifying violence.” Zuckerberg acknowledged that people were “upset” by the decision, “but our position is that we should enable as much expression as possible unless it will cause imminent risk of specific harms or dangers spelled out in clear policies.”

That decision prompted Facebook employees to stage a virtual walkout in protest, and Zuckerberg said late Friday that Facebook would “review” its policies on speech that promotes violence.

A spokesperson for the Chan Zuckerberg Initiative reiterated in an email to The Verge that CZI is separate from Facebook, with separate offices, and a separate mission. “We are grateful for our staff, partners and grantees in this work and we respect their right to voice their opinions, including on Facebook policies,” the spokesperson said.

Facebook did not immediately return a request for comment Saturday.

UPDATE: June 6, 5:59PM ET: Added statement from Chan Zuckerberg Initiative.