LAS VEGAS — Hackers bent on derailing Anonymous clashed with members of the notorious group at a DefCon gathering in Las Vegas late Saturday.

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

"When Anonymous started it was a good idea," Asherah said during what exploded into the fieriest session yet 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."

Asherah presented a history of Anonymous, saying the same people were behind splinter hacker group Lulz Security.

The speakers laughed, cursed, and openly taunted Anonymous while telling of how they were able to identify some members of the group because they used their hacker names at other online venues such as Facebook and Yelp.

Backtrace told of luring Anonymous members into online video chats, capturing images of their faces and getting them to openly talk about illegal antics they have done and with whom.

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 is 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.

The Anonymous member with the mask, which he raised while answering questions, reasoned the cyberattacks conducted in support of whistle-blower website WikiLeaks were noble.

"Working together in the last year, Anonymous and WikiLeaks have done more for world peace than any government has done in the last thousand years," he maintained.

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."

Hubris and Asherah said they share their findings with agents from the US Federal Bureau of Investigation.

"You can expect something pretty spectacular in the next few weeks," Asherah hinted.

"Anonymous thinks they can be jackasses because nobody knows who they are," she said. "Unfortunately, not many of them are truly anonymous. I know who a lot of them are."

Anonymous mouthpiece Gregg Housh scurried to the stage after the talk, noting that the session was filmed and quickly telling a companion "we have to photo bomb" the footage.

Housh, who contended he was not an official spokesman for the group, rejected what Backtrace laid out in the session and said members of Anonymous had showed themselves publicly to disrupt the presentation.

Hubris claimed victory for luring Anonymous members into a public forum.

Asherah said that Backtrace was welcomed in the DefCon community, where many people were unhappy with Anonymous and Lulz for darkening the already shady image of hackers.

"They are peeing in everybody else's pool," Asherah said of Anonymous. "We want to hack in peace and these guys are coming in and making hackers into super villains."