Giant social media firm Facebook acknowledged on Wednesday that it erred in not communicating enough to users that the facial recognition technology currently deployed on its site has been turned on by default.

Such Facebook function, as divulged by online security expert Sophos earlier this week, will automatically identify users whenever they are logged in but the social networking company argued that the new function will only be activated during attempts to upload image files on users account.

A Facebook spokesman told PC World that "Tag Suggestions are only made to people when they add new photos to the site, and only friends are suggested," adding that the features can be disabled on the account settings.

The Sophos disclosure prompted calls for probe coming from officials of the European Union, as reported by Bloomberg, which wanted to determine if the new Facebook feature runs in counter with the region's privacy laws, especially in Ireland and the United Kingdom.

While the European side was quicker to react on the apparent breach of privacy by Facebook, American lawmaker Edward Markey scored the company for turning on facial recognition function on its site without duly advising its users.

In a statement issued by the United States legislator, Markey stressed that "if this new feature is as useful as Facebook claims, it should be able to stand on its own, without an automatic sign-up that changes users' privacy settings without their permission."

According to PC Magazine, the deployment of the new technology was hinted by Facebook back in December 2010, which the company said will make its easier for users to tag pictures of their friends during uploading process by suggestions that will pop out automatically.

Yet with issues coming out that highlight privacy and security concerns, Facebook has admitted that "we should have been more clear with people during the roll-out process when this became available to them."

Despite owning up its mistake, Facebook said that making the feature as an opt-in function is not a consideration at the moment but according to PC Magazine, users who are savvy enough can opt-out by accessing their account's privacy settings.

Upon reaching that page, the publication said that users need to access the 'Customise settings' menu, then proceed to 'Things other share' and explore on the option called 'Suggest photos of me to friends', which they can then tick off to disable the feature.