POLICE say they know why two groups of Sudanese-Australian youths, totalling more than 50, gathered to fight in Melbourne’s northwest on Wednesday night.

Victorian Police Commissioner Graham Ashton says the teens who threw rocks at police and reportedly shouted “police can’t touch us” were planning to clash “over a couple of girlfriends or something like that”.

Mr Ashton told ABC Radio one group was from the northern suburbs and one was from the southern suburbs. The planned fight was stopped by police who received a tip-off and quickly arrived and dispersed those involved.

Commander Tim Hansen confirmed the fight was about “a girl” at a media conference at 1pm today.

“As we’re aware, police became aware of a planned fight,” he said. “Currently, it would appear the genesis of this fight or this agreement to come together from these two disparate groups was based on a teenage relationship issue over a girl.

We’re LIVE with Commander Tim Hansen regarding the Taylors Hill incident overnight. https://t.co/7CkWiaKhuM — Victoria Police (@VictoriaPolice) August 9, 2018

“That quickly became the focus of social media attention and as a result of that two distinct groups of friends met up at this location and the situation escalated rather rapidly.”

Terrified residents of Taylors Hill were told to “stay inside and lock the doors” as police arrived.

Dozens of heavily armed riot and plain-clothed police blocked off main roads and diverted traffic in Taylors Hill and Caroline Springs.

Some of the teens were still wearing their school uniforms when the groups gathered at a basketball court about 5.30pm and began throwing rocks.

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One rock smashed the rear windscreen of a police car.

Mr Hansen said two groups of young African males planned to meet at Taylors Hill following an escalation in “tensions”.

“Our intelligence at this stage is that there is a bit of tension between two groups of young males,” he told Sunrise.

“We are really trying to unpack that and understand that currently. We got some intelligence last night that these tensions were simmering away and likely to come to a head in the western suburbs, so we immediately activated one of our plans and pooled resources.”

Mr Hansen said the violence is “not widespread” and officers are “currently engaged with some of these persons that are operating in what you would call street gangs, I guess”.

Taxi drivers were warned on Wednesday night via their in-car message boards to avoid the area “due to a riot”.

“There were massive groups,” one horrified resident told the Herald Sun.

JUST IN: Disturbing footage of the moment a 100-strong gang went on a violent rampage in Melbourne has surfaced. #9News pic.twitter.com/xmVtLrvVgZ — Nine News Australia (@9NewsAUS) August 8, 2018

“They told me to stay inside, lock the doors and yeah, it’s scary,” another resident added.

One resident of Bronte Way told The Age that police were roaming the area and a helicopter was flying overhead when he came home.

“This has happened multiple times … but it hasn’t happened for a good four or five months,” he said.

“That’s the reason we have roller shutters now. I’m not opening the door. I was told by police to get inside before.”

Another neighbour said Wednesday night’s clash was the “worst yet”.

“We’ve been here nine years and this is the worst yet … You build a nice house in a nice area … you don’t want to start seeing things like that, where is it coming from?” he told The Age.

One of the rioters was heard by residents shouting “police can’t touch us”, according to the Today Show.

Resident tells me he heard youths yell out “Police can’t touch us” as they ran riot in Taylor’s Hill last night @TheTodayShow — Christine Ahern (@ChristineAhern) August 8, 2018

In relation to last night’s riot, a police spokeswoman said: “Police continued to patrol the area and monitor the situation as the youths dispersed and were moved on from the area a short time later.

“A number of specialist units were utilised including the Operations Response Unit and the Public Order Response Team to ensure public safety.”

There were no reports of major injuries. A spokeswoman for Victoria Police told news.com.au this morning that no arrests have been made and officers are still appealing for information.

Mr Hansen defended the fact that police had made no arrests after being pressed by 3AW breakfast host Ross Stevenson.

“People want to know how people can damage a police can in the presence of police, and no one gets arrested?” Stevenson asked him.

Mr Hanson said police had “short-term objectives” to keep residents safe.

“We were really successful at that. We launched an investigation overnight. I just want to reassure everyone we take a zero tolerance with this sort of behaviour.

“You’ll certainly see some movement in the investigation and arrest space in coming days.”

The dramatic scenes come after a crime spree in Taylors Hill in January when two teenagers were attacked and two homes were broken into during a four-hour rampage in Melbourne’s western suburbs.

In one incident, a 17-year-old was ambushed and hit with what appeared to be a baseball bat after refusing a demand for his belongings.

The terrified teenager was then dragged along the ground before the offenders fled in a car.

Do you know more? Email rohan.smith1@news.com.au