(CNN) -- Facebook's facial-recognition feature for automatically tagging uploaded photos with the names of those pictured sparked a backlash from privacy advocates. Now it's coming under scrutiny from Connecticut's attorney general, who sent a letter to company officials this week requesting a meeting.
Connecticut Attorney General George Jepsen said he has "deep concerns" about Facebook's choice to make the tagging feature opt-out, not opt-in.
"The potential uses of facial recognition on this scale remain unclear but concerning," Jepsen wrote. "This important privacy issue needs to be addressed promptly. There may be some fairly simple changes that can be implemented to make certain that consumers are fully aware of the implications of 'Tag Suggestions.'"
Facebook first introduced its "Tag Suggestions" tool in December, but it has recently accelerated the feature's worldwide roll-out to the site's 500 million members. Four privacy advocacy groups, including the Washington-based Electronic Privacy Information Center (EPIC), banded together last week and filed a complaint with the U.S. Federal Trade Commission. They asked the FTC to require Facebook to cease using facial recognition technology without users' explicit, opt-in consent.
A Facebook representative said the company is in contact with Jepsen's office and is "eager" to explain more about how Tag Suggestions works. However, Facebook is standing behind the tool and its widespread deployment.
"Since last December, we've been gradually rolling out the feature and millions of people have used it to add hundreds of millions of tags," Facebook said in a written statement. "This data, and the fact that we've had almost no user complaints, suggests people are enjoying the feature and are finding it useful."
Facebook members who don't want their name to come up in the suggestions tool can disable it in their "privacy settings" panel. Facebook offers instructions for how to do that in its blog and in its "help" pages. Members can also un-tag themselves from a photo at any time.
But EPIC and other critics say those tools are too difficult to use, and that the onus should be on Facebook to expressly confirm users' consent -- not the other way around.
That issue is also at the heart of Jepsen's gripe.
"In Facebook's desire to promote photo sharing and tagging among its users, it appears to have overlooked a critical component of consumer privacy protection -- an opt-in requiring users to affirmatively consent," Jepsen wrote in his letter.
Government regulators and policymakers are growing increasingly concerned about how tech companies handle user privacy.
Senators Al Franken and Richard Blumenthal introduced legislation this week that would require the makers of mobile software and devices -- like Apple's (AAPL, Fortune 500) iPhone and Google's (GOOG, Fortune 500) Android -- to receive express opt-in consent from users before tracking their locations. 
