A 10-year-old boy has been hit in the head with a rock in Cooloongup.
The boy and his brother were riding to their uncle's house when they were approached by teenagers on a cycle path near Rockingham Train Station around 11.30am on Sunday.
Caleb McAlister told Nine News the offenders demanded they hand over their bikes, before he was hit with a rock.
"Me and my brother got off our bikes because they threatened us to a fight and (they) ditched a rock at my head," he said.
"We gave up our bikes so my brother made sure I didn't get hurt anymore."
Caleb suffered a wound just above his eye.
His mother took him to hospital for treatment.
Anyone with information should contact Crime Stoppers on 1800 333 000.

The boy's bikes were stolen by the offenders. PIC: Facebook
Mandurah Crab Fest boasts huge range of free, family friendly entertainment
Fuel prices surge in Perth, Mandurah
Teen boys charged over Mandurah burglaries
Tragic update in search for missing man Robert Snyder
Premier Roger Cook to leave Kwinana electorate, move to Perth
Mandurah Marine Rescue's new vessel named in memory of nun who survived 1959 boating accident
Teen dies in motorbike crash at Waroona Dam
Shark alert issued after whale carcass reported at Preston Beach
Kwinana businesses to refuse serving students during school hours