Privacy groups asked the Federal Trade Commission to prevent Facebook Inc. (FB) from changing its data use policies on concern with how the social network operator handles user information for advertising.

The proposed update would violate the company’s policies and an earlier settlement with the FTC, according to a letter to the agency dated yesterday and signed by officials at six groups, including the Electronic Privacy Information Center. Facebook last week proposed to clarify how it manages data for advertisements as part of an agreement stemming from a settlement of a class-action lawsuit.

“The Federal Trade Commission must act now to protect the interests of Facebook users,” the letter said. “The right of a person to control the use of their image for commercial purposes is the cornerstone of modern privacy law.”

Facebook has come under scrutiny for how it handles personal information at the world’s largest social-networking service. The company has faced multiple privacy flaps over the past few years, which it has taken steps to address. In late 2012, Facebook unveiled new privacy tools that provided shortcuts for managing settings, including what members can see on user accounts.

The company said updates to its “Data Use Policy” and “Statement of Rights and Responsibilities,” seek to add clarity for members.

“We revised our explanation of how things like your name, profile picture and content may be used in connection with ads or commercial content to make it clear that you are granting Facebook permission for this use when you use our services,” Debbie Frost, spokeswoman for the company, said in an e-mailed statement. “We have not changed our ads practices or policies.”

Others privacy groups to sign the letter to the FTC include the Center for Digital Democracy and Patient Privacy Rights.

The letter said the new rules “will allow Facebook to routinely use the images and names of Facebook users for commercial advertising without consent.”

To contact the reporter on this story: Brian Womack in San Francisco at [email protected]

To contact the editor responsible for this story: Pui-Wing Tam at [email protected]