Police are appealing for witnesses following an aggravated car robbery at Stromlo High School in Waramanga on Thursday.
ACT Policing received a report about 11.45am that a male offender armed with a knife had approached another male and demanded his vehicle.
The alleged offender assaulted the male and then fled in the vehicle. An extensive police search has yet to locate the vehicle or offender.
The alleged offender is described as Caucasian, about 170cm tall, of slim build, with dark hair. He was wearing a bright coloured singlet and may be travelling with another male.
The car is a blue 2009 VE Holden Commodore sedan with ACT licence plates YKP10R. It was displaying red provisional plates at the time of the robbery.
Police are seeking public assistance and witnesses to the incident on 131 444.