A 12-year-old boy arrested for stabbing vapers

A 12-year-old boy has been arrested for his alleged involvement in a series of armed robberies in Sydney's west.

The boy was arrested after the incidents on Sunday evening.

He was refused bail and is due in Parramatta Children's Court on Monday.

The first alleged incident took place at a tobacco shop on Melville Road, St Clair. Around 8:45 p.m., the boy allegedly demanded money and vapes before threatening the attendant with a knife, police said.

He obtained vapes and an energy drink, and the employee was not physically injured, according to police.

Around 10 p.m., police say the same boy went to a gas station on Banks Drive, St Clair.

At the gas station, police said the boy threatened the attendant with a knife while demanding money and cigarettes.

The employee was not physically injured and the boy was not given any items.

Police then arrested the 12-year-old near the St Clair Alpine Circuit.

He was taken to Penrith Police Station and charged with robbery with an offensive weapon and claiming property with threats with intent to steal.