A motorist and his passengers were dragged from their car and assaulted with a tree branch in Lathlain overnight.
A police spokeswoman said about 10.45pm the 34-year-old man was driving on Cornwall Street when two men stood in the middle of the road in front of their vehicle.
After swerving to avoid the pair, the car crashed into a kerb.
A larger group of four to six people approached the car and began throwing objects at the vehicle and yelling abuse at the driver.
He was then dragged from the car by three males and assaulted.
A 28-year-old female passenger was also dragged from the vehicle and hit in the face. The pair were then assaulted with a branch from a tree.
The other passengers, two women aged 63 and 61, were ordered out of the car. The 63-year-old was assaulted.
After being told the police were on their way, the gang fled towards Gallipoli Road.
All four victims were taken to Sir Charles Gairdner Hospital with minor injuries.
All offenders are described as dark skinned.
Anyone with information should call Crime Stoppers on 1800 333 000.