Teens charged over armed robbery spree

Two teenage boys have been charged over an alleged armed robbery spree across Sydney involving a shortened firearm, a sword and a machete.

Police say the two boys, aged 17 and 15, were arrested during a vehicle stop on Friday night following another armed robbery at a Lane Cove convenience store.

The boys were treated by paramedics for minor injuries and taken to hospital for observation, with the 17-year-old since discharged and refused bail to appear in a children's court on Saturday.

The 15-year-old remains in hospital under police guard.

Their charges include robbery armed with an offensive weapon causing wounding.