Five youths have been accused of assaulting three teenage boys in Melbourne's west with machetes, poles and knives.
The group of males was allegedly armed with the weapons and approached the trio in a Werribee park about 6.45pm on October 31, Victoria Police said on Friday.
A 17-year-old was struck with a machete suffering serious injuries to his lower body. He managed to run away to a nearby property but was followed and threatened.
Two 18-year-olds fled the scene, but the group followed them, attacking them with with machetes, poles and knives, police said.
One teen suffered a head injury and all three ended up in hospital.
Detectives on Friday acted on nine warrants across Melbourne's north west and arrested six males, but later released one without charge.
The charged youths include a 14-year-old and two 15-year-olds.
They will face children's court at a later date accused of violent disorder, weapon possession and committing an indictable offence on bail.
Two young men aged 21 and 22 will face court on similar charges.
Police are asking any witnesses of the incident to contact Crime Stoppers on 1800 333 000.