UN human rights experts looking into a possible genocide in Myanmar said Facebook had played a role in spreading hate speech there, Reuters reported.
The social network offered no immediate comment on the criticism yesterday, although in the past the company has said that it was working to remove hate speech in Myanmar and bar people who indulge in hate speech.
Over 650,000 Rohingya Muslims have taken refuge in Bangladesh after fleeing Myanmars' Rakhine state after insurgent attacks led to a security crackdown last August.
There have been many harrowing testimonies of executions and rapes by Myanmar security forces.
The UN human rights chief said last week he strongly suspected there had been acts of genocide against the Rohingyas to which Myanmar's security adviser had called for "clear evidence".
According to Marzuki Darusman, chairman of the UN Independent International Fact-Finding Mission on Myanmar, social media had played a "determining role" in Myanmar.
"It has ... substantively contributed to the level of acrimony and dissention and conflict, if you will, within the public. Hate speech is certainly of course a part of that. As far as the Myanmar situation is concerned, social media is Facebook, and Facebook is social media," he said, Reuters reported.