THREE youths — including a boy aged 10 and girl aged 13 — have been arrested after a gang rampaged through the southern suburbs, savagely attacking residents with a garden stake, damaging cars and throwing rocks at vehicles on the Southern Expressway.

Witnesses have told how the group relentlessly beat a couple, leaving one victim “covered in blood from head to toe”.

Shortly afterwards the gang — who were described as being of Aboriginal appearance — threw rocks at cars from a footbridge over the Southern Expressway before they assaulted a man and woman at their home.

Three youths were arrested just after midday at a home in Hackham West for the violent rampage.

A 13-year-old girl and a 10-year-old boy from Hackham West were arrested, along with a 16-year-old boy from Seacombe Gardens.

The 10- and 13-year-olds were both charged with aggravated assault causing harm, aggravated assault and serious criminal trespass.

They were granted bail and will appear in court at a later date.

The 16-year-old was charged with the same offences as well as breaching bail and property damage.

He was refused bail and will appear in court this week.

Investigations into the string of incidents are continuing and police are not ruling out further arrests.

The first incident occurred just after 11.45pm on Saturday with police receiving reports of a fight in Columba St, Morphett Vale.

Police say a male motorist had been driving along the street when rocks were thrown at his car.

When he stopped and approached the youths, believed to be four boys and a girl, they assaulted him and damaged his car using sticks and rocks.

Andrew Craigie, 60, was at home when the youth walked past his house and “gave me a mouthful”.

Mr Craigie said the group moved on but shortly after he heard an altercation.

“A ... car went past and (the driver’s) yelling and screaming at them so I don’t know what they’ve done to him,” he said.

Mr Craigie said the motorist told him the youths had thrown rocks at his car.

He said the group turned on the driver further up the street.

“It just got out of hand,” Mr Craigie said.

“(One of the youths) was trying to smash a window, trying to get (the driver) out and the girlfriend is going off.

“He just drove through the whole crowd and knocked one over.”

Mr Craigie said the youth who was struck by the vehicle ran off and the driver then stopped in the street, but was again attacked.

“(One youth) got a (garden stake), broke the window and hit him about nine times while he was sitting in the car,” he said.

“When I got to him, he was just covered in blood from head to toe.

“The skinny one came back ... and got (the garden post) and swung it around and hit him in the head. Then he just ran at him and jumped and kicked him in the chest and he fell back.”

Mr Craigie stayed with the victims while they waited for police.

He said the female victim was also attacked during the incident.

“It was just a shocking thing to watch,” he said.

“I’ve seen some things in my years but that was just nasty.”

Another neighbour, who did not wish to be named, heard a commotion in the street and saw the victims being attacked.

“I heard them saying ‘we’re going to go back and get this white fella’ so he went back ... and stabbed right through the window (with a garden post),” the neighbour said.

The neighbour said it was not uncommon for violent incidents to occur in the area.

“They’ve got to realise this is a family neighbourhood — (we) just don’t need it,” he said.

The male victim was taken by ambulance to Noarlunga Hospital with facial injuries.

The youths ran off before police arrived.

Then just after midnight, a car travelling south on the Southern Expressway at Noarlunga Centre drove over some concrete.

As the driver stopped to check for damage, rocks were thrown at his car from the Poznan Path footbridge.

The victim was not injured during the incident and his vehicle sustained minor damage.

About half an hour later, residents at a home in Oslo Crescent, Hackham West, called police after discovering a group of youths on the roof.

The two residents confronted the youths who then assaulted them.

Both victims were taken to Noarlunga Hospital for treatment but released about 5am. They declined to comment about the incident.

The police helicopter and STAR Group officers attended the scene but were unable to find any of the suspects.

A neighbour, who did not wish to be identified, said he was woken by the youths shortly before they attacked the couple.

“About 12.30am ... I was in bed and the front security lights came on and two young lads, I could hear their voices and then they put our bin against the fence and jumped over and went around the back of our place, along the fence and over into the neighbour’s (yard).

“Then we heard the police chopper.”

The neighbour said he did not go outside for fear of being attacked.

Another neighbour said she was “not game enough to go outside after night-time”.

Police believe all three incidents are linked and continuing their investigations.

In response to the rock-throwing incident on the Southern Expressway, Transport Minister Stephan Knoll said he had ordered an “urgent review” of preventive safety measures.

“These acts of random violence are totally unacceptable and I hope the perpetrators are quickly caught and punished,” he said.

“Improving public safety will be a hallmark of the Marshall Government.”

Anyone with information is urged to call Crime Stoppers on 1800 333 000 or report it online at crimestopperssa.com.au.

Timeline

11.45pm Saturday: The gang attacks a man and a woman after throwing rocks at their car. A garden post is used to smash the vehicle and hit the male victim.

Just after midnight Sunday: The gang throws rocks from the Poznan Path footbridge at cars travelling along the Southern Expressway. They damage a car but the driver is not injured.

Just after 12.30am Sunday: The group climbs on to the roof of an Oslo Crescent, Hackham West, home. When the male and female occupants confront the youths, the gang assaults them.

12.20pm Sunday: Police arrest a 13-year-old girl and 10-year-old boy, both from Hackham West and a 16-year-old boy from Seacombe Gardens over the attacks.