A splinter group of notorious hacker collective Anonymous was fomenting support Wednesday for a plan to "kill" online social networking star Facebook.

A YouTube video labeled as a message from Anonymous claimed that "Operation Facebook" would take place on November 5 to destroy the social network for supposedly abusing the privacy of users.

An Anonymous spokesman told AFP that even heads of the group were uncertain how seriously to take the threat since the loosely-knit organization doesn't have a strict command structure and members mask their identities.

"I found groups of people who say we absolutely are and have a trick up our sleeves," said the spokesman. "I found others that say it isn't us and that this is stupid."

The video displayed a gray image of the Anonymous logo as a digitally masked voice announced a plan to destroy Facebook and called for others to join in the cyber attack.

The video accused Facebook of holding onto the data people post in accounts and of even sharing some of it with law enforcement agencies.

"Join the cause and kill Facebook for the sake of your own privacy," the speaker urged in the video, which has been viewed more than a million times since being posted three weeks ago.

A cadre within Anonymous was evidently trying to rally cyber warriors in a Facebook attack, but the plan did not have the backing of the majority of the group, according to the spokesman.

A message on an "Anonops" account at microblogging service Twitter acknowledged that some members of the group were organizing a Facebook attack but that didn't mean the sentiment was unanimous.

"This could be as dumb as one person making a video or as big as someone having already broken into the Facebook network," said the Anonymous spokesman.

Facebook declined a request for comment.

Hackers bent on derailing Anonymous clashed with members of the group at a DefCon gathering in Las Vegas over the weekend.

"Hubris" and "Asherah" of startup Backtrace Security condemned Anonymous for "bully behavior" and argued that the group was trying to pass of reckless opportunism as Internet-age activism.

"When Anonymous started it was a good idea," Asherah said during what exploded into a fiery session at the infamous DefCon hacker get-together.

"Now, it is in violent freefall," she continued as the audience divided into opposing camps of hackers cheering in agreement and angry Anonymous fans heckling and shouting.

"We are trying to derail something that has gone wrong very quickly and is going to get worse."

The session turned into a shouting match when representatives of Anonymous interrupted from the audience and then joined Hubris and Asherah on stage to field questions.

"I believe what (Anonymous is) doing is for the good of everyone," said an Anonymous member with a mask similar to the one worn by the protagonist in the film "V for Vendetta," sparking applause from one side of the large room.

Anonymous representatives, one in a toy bear costume, defended actions such as releasing looted computer data including names of police informants or credit card numbers on the grounds networks should be better protected.

Asherah portrayed Anonymous as a formless mob that does what it feels and then justifies it after the fact, often under the guise of activism.

"They have become the monsters they are claiming to fight against," she said. "If anonymous wants to be taken as a legitimate activist group they need to excise the bullies and the jerks."