A video of teenage girls fighting as onlookers stand back is cause for concern, a Vancouver psychologist says.

The nine-minute video shows four girls wrestling, slapping each other and pulling hair as a crowd watches, mostly off-camera.

The video was posted to YouTube last week, and had more than 1,100 views before it was removed by the user. The person who posted the video told CTV that the fights weren't real, and that the girls in the video were just acting.

He said the video was shot by a relative, and that he'd put it online hoping to make some money off it.

"If YouTube plays an ad on my video then YouTube will pay me for that advertisement," he explained.

But someone who claims to know the girls in the video told CTV News the fight, which they say occurred two weeks ago, was over boys and drugs.

Another video was posted online on Monday, by a different user. The videos show the same scenario from different angles.

An RCMP officer told CTV that he was aware of the videos.

The videos show two teen girls fighting for several minutes, then another two other girls fighting a short distance away immediately after the first fight.

Onlookers are heard laughing, swearing and gasping, and many are holding cameras or cellphones.

A teenage boy can be heard telling someone to call the police, and another yells, "Don't pull hair, you just said no pulling hair."

Later, another person yells, "bad hair day!" as the girls pull each other's hair and he laughs.

At one point, one of the girls tells another, "Don't cry" as she pins her opponent to the ground with her knee, then hits her in the forehead. The beaten girl later walks away from the fight and appears to be bleeding.

A few minutes later, a third teen pins a fourth to the ground, straddles her chest and appears to punch her repeatedly in the face. After a few seconds, someone can be heard saying that the fight is "unfair" and a teen boy intervenes, pulling the girls apart.

"No guys jumping in!" someone yells in the background after the girls are separated.

"Do you want to f---ing fight me or not?" one of the girls yells, and the girls start fighting again.

But a Vancouver behavioural specialist told CTV News that perhaps even more disturbing than the fight is how the onlookers responded.

"I was highly concerned when I saw this," clinical psychologist Dr. Joti Samra said of the video.

"It's troubling at so many levels: Troubling that these young kids are engaging in this type of behaviour; troubling that so many are standing around watching and not intervening; and troubling that people are documenting this and putting this up in a permanent forum on social media."

Samra said the fight seemed "intentional," with an audience armed with smartphone cameras, and some sort of pre-defined rules evident by their comments.

"And the fact that kids are allowing this to happen and not intervening is highly troubling for everyone that's involved," she said.

The disturbing video is not the first time footage of teen fights have gone viral. Earlier this year, a YouTube channel popped up with a playlist of numerous short videos of Surrey high school girls kicking and slapping each other.

Samra said posting videos like the Surrey fights can desensitize their viewers to similar events in the future. Those involved and those watching the video afterwards start to have a "reduced emotional reaction" to seeing this kind of violence, she said.

"That's really our trigger, our cue, to act and do something, and that's really getting washed away when people are repeatedly watching something of this nature," she said. Repeated exposure to violence can make some people less likely to intervene.

Though Samra acknowledged that disagreements and sometimes even physical fights can be a normal part of growing up, she said the videos take it to another level by "making a production" of conflict.

"The intent and outcome here is different than what we see in the usual type of conflicts. There's a very intentional component here that's meant to entertain others, for lack of a better word," she said.

"That's absolutely the wrong message that we're giving."

With a report from CTV Vancouver's Michele Brunoro