"(Social media) has ... substantively contributed to the level of acrimony and dissention and conflict, if you will, within the public a Hate speech is certainly of course a part of that," said Darusman.
"I'm afraid that Facebook has now turned into a beast, and not what it originally intended," she said.
Lee was speaking at the UN's Human Rights Council in Geneva.
Facebook did not immediately comment on the fresh charges.
Lee, who was banned from Myanmar last year after it claimed a previous report by her was biased and unfair, said she had seen evidence that Myanmar's military was continuing to target the Rohingya, razing their villages.
The government ordered internet and mobile service providers to temporarily block Facebook, WhatsApp and Instagram, as well as messaging service Viber, after officials said these platforms were fueling online hate speech.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)