A 16-year-old boy has died after being stabbed in Bristol.Medics tried to save the teenager but he was pronounced dead in the St Philips area of the city on Wednesday evening.Avon and Somerset Police said the boy was attacked by two people wearing masks who then fled on bicycles.He ran to get help after the attack but collapsed and was helped by a motorist before emergency services arrived.The killing comes weeks after the deaths of Mason Rist, 15, and Max Dixon, 16, who were stabbed in the Knowle West area of the city.Bristol Commander Superintendent Mark Runacres said: "Tragically, we have lost another young life from our city in utterly horrific circumstances.