A teenager has been charged over a violent attack in Melbourne on a boy walking home from school that left him with life-threatening injuries.

The 14-year-old was confronted by a group of offenders as he left Glen Eira College in Glen Huntly on Monday afternoon.

He was forced into a car and seriously injured after coming out of the vehicle while it was moving.

On Friday, a Frankston boy, also 14, was charged with a string of offences including armed robbery, conduct endangering life, intentionally causing serious injury and theft.

He was set to appear at a children’s court later in the day.

On Thursday, Inspector Scott Dwyer said investigators had identified all those alleged to be involved and warned their arrests were “imminent”.

Detectives are probing whether it is linked to other recent violent incidents in the area.

About 10 minutes prior, two people armed with machetes robbed four teenagers in the same suburb but police are yet to confirm whether the two incidents are linked.

Extra patrols have been rolled out in the Glen Eira and Bayside areas near where the attacks happened as a precaution.

Insp Dwyer urged the public not to be alarmed as officers hoped to deter crime.

– AAP