Two teenagers have been killed and two children are seriously injured following a collision involving off-road motorbikes in Melbourne's west.
The crash happened on Beatty's Road at Grangefields, about half an hour from Melbourne's CBD, at 6.35pm on Sunday.
Victoria Police said at least two off-road motorbikes and potentially a quad bike were being ridden when the crash happened but the exact circumstances surrounding the collision are still under investigation.
An 18-year-old Altona Meadows woman died at the scene and a 17-year-old Hoppers Crossing boy was taken to hospital with life-threatening injuries, where he later died.
A six-year-old boy and an 11-year-old boy were taken to hospital with serious injuries.
A 43-year-old Altona Meadows man was also hospitalised with non-life-threatening injuries.
"Motorcycles are not toys, they can be lethal weapons" Detective Sergeant Richard Wood told ABC TV.
"It's two lives tragically lost needlessly."
Victoria's road toll has risen to 202, up from 162 this time last year.
Anyone who witnessed the incident, has footage or information about what happened is urged to contact police.