Strike Force Trident charged 4 youths yesterday after multiple aggravated robberies in the northern suburbs.

At 1 am, two males, aged 13 and 16, and two females, aged 14, attended a service station in Casuarina and allegedly stole several small items before threatening an employee with a metal bar and fleeing the scene.

Around 7 am the same day, the youths were involved in an altercation in Moil. The 13-year-old male allegedly assaulted a taxi driver with a chain before all four youths stole his vehicle.

With assistance from the Dog Operations Unit and Strike Force Trident detectives, they arrested all four youths at separate residences throughout the day. Police located the abandoned taxi in Gray.

All have been charged with aggravated robbery, aggravated unlawful use of motor vehicle, stealing and property damage.

Three youths will appear in court today, with the remaining youth bailed to appear at a later date.