Social-networking site Facebook came under fire earlier this week for tracking users’ Internet activities even after they log out of the site.

Reps. Edward J. Markey and Joe Barton urged the Federal Trade Commission (FTC) to launch a probe into the Facebook’s use of “cookie” software under the “unfair & deceptive acts” clause of the agency’s directive.

In their letter to the FTC, the congressmen wrote, “When people log out of Facebook, they are under the expectation that Facebook is no longer monitoring their activities. We believe this impression should be the reality.”

Ten public-interest groups, including the Electronic Privacy Information Center and the American Civil Liberties Union, also requested the FTC to scrutinize Facebook’s super cookies that allow the site to track users’ online activities even after they log out.

The FTC is yet to disclose if it would it launch an investigation or not.

Meanwhile, the Irish Data Protection Commissioner’s office has confirmed that they would conduct a privacy audit of Facebook’s activities outside the United States and Canada as they received twenty-two complaints.

Facebook is the world’s most popular social network, with more than 750 million users.