Youth holds up Para Hills service station

A teenage boy has held up a service station at Para Hills, in Adelaide's northern suburbs, early this morning.

At around 1.30am, the boy, believed to be around 15-years-old, forced his way into the closed doors of the BP service station on Bridge Rd.

Armed with a knife, South Australian police say he threatened the console operator, and ran out with cash.

He was last seen heading north along Bridge Rd, but a police search with a sniffer dog failed to find him.

The youth is described as being of Aboriginal appearance, around 160cm tall and of slim build.

He was wearing a grey hooded jumper and cream coloured shorts.

The console operator was not injured.

Police are asking anyone with further information on the incident to contact BankSA Crime Stoppers on 1800 333 000 or go to their website.