We told you how some employers and government agencies are requiring job applicants to give up their passwords to social networking sites? Facebook is not amused.

Talking Points Memo reports that Facebook is threatening to sue to protect the privacy of users. Chief privacy officer, Erin Egan, says employers who want to poke around in an applicants profile are actually opening themselves up to liability issues.

Egan notes that the company has been tracking the reports of employers logging into employee’s Facebook accounts for “months,” and has seen a “distressing increase” in the reports.

“This practice undermines the privacy expectations and the security of both the user and the user’s friends. It also potentially exposes the employer who seeks this access to unanticipated legal liability.”

Later, Facebook cites some examples of the liability employers may face:

For example, if an employer sees on Facebook that someone is a member of a protected group (e.g. over a certain age, etc.) that employer may open themselves up to claims of discrimination if they don’t hire that person.

The bottom line: Facebook says it will do what it takes to stop people from peering on user’s profiles, whether that means leaning on lawmakers to slapping employers with lawsuits.

“Facebook takes your privacy seriously. We’ll take action to protect the privacy and security of our users, whether by engaging policymakers or, where appropriate, by initiating legal action, including by shutting down applications that abuse their privileges.”