LOS ANGELES — For roughly 24 hours, Facebook's news feed was not a family-friendly place.

Facebook acknowledged Tuesday that the social networking site was briefly infested with a mix of hard-core pornographic images, doctored pictures of celebrities in sexual situations, photos of extreme violence and even a picture of a beaten dog.

Facebook said it had identified the problem — if not the culprit.

During the attack, users mistakenly downloaded malicious programming language that resulted in their sharing offensive images on Facebook without knowing it, a company spokesman said, adding that the website's engineers were working on a fix.

Facebook said it built mechanisms to quickly shut down the malicious pages and will put users who were affected by the offensive spam through "educational checkpoints" so they know how to protect themselves from further incidents.

The next step for Facebook is figuring out who is behind the attacks.

"We are now in the process of investigating to identify those responsible," Facebook spokesman Andrew Noyes said.

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Update: Facebook confirms nasty porn storm