Willaston robbery: Boy robbed at knifepoint before police officer struck

A police officer had to be hospitalised after being struck while arresting teenagers involved in a violent knifepoint robbery in a northern suburbs park.

Three teenagers allegedly robbed a boy at knifepoint before assaulting a police officer leaving them in hospital north of Adelaide.

The victim was walking through Clonlea Park at Willaston about 5.45pm Wednesday when two boys and a girl confronted him with a knife.

The suspects stole his shoes, mobile phone, airpods and a gold chain.

After reporting the incidents to police, the suspects were identified within the park, and all three were arrested while the property was recovered at the park.

During the arrests, the boy allegedly struck a police officer in the face causing him an injury to the eye which required hospital treatment.

The Kilburn boy, 15, was charged with aggravated robbery, aggravated assault causing harm to an emergency services worker and resisting police.

He will face Adelaide Youth Court on Friday.

The Evanston Gardens girl, 15, was charged with aggravated robbery and hindering police.

She was bailed to face court in September.

Investigations are ongoing to locate a third suspect, and police urge anyone with information to call Crime Stoppers on 1800 333 000.