Four people, including three teenagers, have been arrested and police are looking for a fifth after a restaurant owner was assaulted at Christies Beach on Thursday night.

The owner of Southern Palace Chinese Restaurant, in Adelaide’s southern suburbs, was taken to hospital with serious injuries after he was set upon by a group of five around 11:45pm on Thursday.

During the alleged assault, the man was stabbed in the hand and punched in the head.

Police arrested four suspects on Friday evening, including a 17-year-old boy from Old Reynella, two 18-year-old men from Christies Beach and a 20-year-old man from Moana.

All four were charged with aggravated assault causing serious harm and aggravated robbery and were refused bail to appear in court on Monday. 

Police believe they know the identity of the fifth suspect and urge him to turn himself in.

Police arrest 17-year-old over shooting incident

Meanwhile, police arrested a 17-year-old boy from Smithfield earlier on Friday over firearm incidents in the northern suburbs last week.

It was the sixth arrest in relation to the incidents last Friday, where shots were reportedly fired at a house at Elizabeth Vale and between cars driving along Main North Road.

Last Sunday, four men and a woman were arrested.

On Friday, the 17-year-old boy was charged with offences including discharging a firearm, aggravated affray and three counts of acts to endanger life.

A composite image of a blue and silver car
Police have released images of the two cars they believe were involved in a shooting incident on Main North Road last Friday.(Supplied: SAPOL)

He was refused police bail and is expected to appear in the Youth Court on Monday.

Police believe all incidents are linked and all parties are known to each other.

There have been no reported injuries to members of the public.

Investigators have released images of the two cars they believe were involved in the shooting incident, and have appealed for information from the public as the investigation continues.