Image: Brisbane Times

Police have arrested and charged four teenage boys following a series of violent carjacking offences in Brisbane’s south.

A group of boys allegedly attacked a man at a service station on Fairfield Road, Yergona on Tuesday night.

They demanded he hand over his car keys and it’s alleged one of the buys produced a knife and used it to cut the man on the neck

Members of the public stepped in and the group fled on foot.

A short time later, they allegedly assaulted another driver nearby, forcing him out of the driver’s seat before stealing his vehicle.

Early Thursday morning a group of boys allegedly confronted another man at Plum Street, Runcorn and threatened him with a gun and a knife, before stealing his BMW convertible.

A 15-year-old boy, a 16-year-old boy and two 17-year-olds have been charged with a string of offences.