from www.foxnews.com – Facebook is investigating reports of a massive wave of pornographic and violent images being posted to its website.

The content — in the form of links, videos, and images — began to appear Monday and includes doctored photographs of celebrities such as Justin Bieber in compromising situations, acts of violence and self-mutilation and even bestiality.

“We have recently experienced an increase in reports and we are investigating and addressing the issue,” Facebook spokesman Andrew Noyes told FoxNews.com.

“We are always working to improve our systems to isolate and remove material that violates our terms. Protecting the people who use Facebook from spam and malicious content is a top priority for us.”

The flood of explicit material appears to be linked to some sort of spam virus that propagates when unknowing users click on infected content, according to tech site ZDNet.

Facebook users took to Twitter to vent their rage, some even threatening to quit the social network once and for all.

“Facebook, I can handle old person porn but please no more beaten, bloody animals … NOT COOL,” complained one.

“Seeing a dead dog on my Facebook newsfeed… Officially deactivating it,” another person tweeted.

“Our parents & grandparents the only ones still on facebook & suddenly a porn section pops up,” joked one user. “Awkward.”

Graham Cluely, a senior technology consultant from Internet security firm Sophos, said it was not yet clear how the malicious content was being spread, but added that the website could face long term consequences.

“It’s precisely this kind of problem which is likely to drive people away from the site,” he wrote in a company blog.

“Facebook needs to get a handle on this problem quickly, and prevent it from happening on such a scale again.”