Zuckerberg says Facebook will review content policies amid criticism

• Zuckerberg's public announcement echoed much of what he said to employees during a company question-and-answer session earlier this week, according to a recording Vox obtained.

Notably, Zuckerberg ended his public message by declaring that "black lives matter."

• In 2016, he condemned incidents of employees crossing off "Black lives Matter" postings on office walls and writing "All Lives Matter" over the top, calling the actions "disrespectful" and "malicious."

Go deeper: Read Zuckerberg's full memo.