Two privacy advocacy groups urged Facebook on Monday to withdraw proposed changes to its terms of service that would impact the privacy of users and their ability to participate in site governance.

Facebook on Wednesday outlined a proposal to end the voting part of the site governance process, restrict users' ability to prevent unwanted messages, and combine personal information from Facebook with Instagram.

EPIC, along with the Center for Digital Democracy, has asked Facebook to withdraw the proposed changes.

In a letter to Facebook Chief Executive Mark Zuckerberg , the groups say "because these proposed changes raise privacy risks for users, may be contrary to law, and violate your previous commitments to users about site governance, we urge you to withdraw the proposed changes."

"Facebook is subject to the terms of a recent settlement with the Federal Trade Commission that prohibits the company from changing privacy settings without the affirmative consent of users or misrepresenting the privacy or security of users' personal information," the groups added.

Regarding Facebook's decision to combine personal information from Facebook and Instagram, the gropps said:

"Earlier this year, a similar data consolidation by Google prompted objections from privacy organizations, members of Congress, 21 European data protection authorities, and IT managers in the government and private sectors. Thirty-sixstate attorneys general sent a letter to Google claiming that the data consolidation "invade[d] consumer privacy by automatically sharing personal information consumers input into one Google product with all Google products" and that it made more of [consumers?] personal information vulnerable to attack from hackers and identity thieves."

In the proposed changes, Facebook also wanted to eliminate a setting for users to control who can contact them on the social network's email system. The company said it planned to replace the "Who can send you Facebook messages" setting with new filters for managing incoming messages.

"By removing users' ability to prevent strangers from sending unwanted messages, the proposed changes are likely to increase the amount of spam that users receive," the groups' letter reads. "Facilitating spam violates users' privacy and security, as many Facebook scams are accomplished through the messaging feature."