WASHINGTON – A privacy-rights group said Thursday it is asking the Federal Trade Commission to examine Facebook’s tracking of Internet users after they log off the world’s most popular social-networking service.

The Electronic Privacy Information Center filed a letter with the FTC Thursday, according to Marc Rotenberg, the Washington-based group’s executive director. The group is also asking the agency to examine whether Facebook’s new Ticker and Timeline features boost privacy risks for users by combining biographical information in an easily accessible format, said David Jacobs, consumer protection fellow for EPIC.

“We would like the FTC to investigate the extent to which Facebook’s recent changes and its secret tracking of users after they have logged out constitute unfair or deceptive business practice,” Jacobs said in a telephone interview.

Facebook, based in Palo Alto, Calif., is adding features to entice users to spend more time on the site and avoid losing them to Apple and Google, which also offer video and music services. Last week, Facebook Chief Executive Officer Mark Zuckerberg unveiled new ways for members to use the social network to share music, movies, television shows, news and activities such as cooking and exercising.

The letter to the FTC references a Sept. 25 blog posting by Australian blogger Nik Cubrilovic, who wrote that Facebook placed so-called “cookies” on users’ browsers that tracked their Internet activity even after they logged out of Facebook. Although Facebook moved to resolve the issue, “it’s unclear how complete the fix is,” Jacobs said.

“There was no security or privacy breach,” said Andrew Noyes, a Facebook spokesman. “Facebook did not store or use any information it should not have.”

Facebook has “no interest in tracking people,” engineer Gregg Stefancik said in a recent blog post. “We do not share or sell the information we see when you visit a website with a Facebook social plugin to third parties and we do not use it to deliver ads to you.”

The letter to the FTC is also signed by public interest groups including the American Civil Liberties Union, The American Library Association, the Bill of Rights Defense Committee, the Center for Digital Democracy, the Center for Media and Democracy, Consumer Action, Consumer Watchdog, PrivacyActivism and Privacy Times.