An eight-year-old boy was pinned to the ground and stabbed with a hypodermic needle.
The boy, who has not been identified, was attacked by two youths in waste ground in Cheltenham, Gloucestershire, on Saturday afternoon.
The eight-year-old had been walking in the Arle Road area of the town with his brother and another friend when they were approached and then chased by the older teenagers.
The boy was pinned to the ground by one of the teenagers and stabbed with the needle. Police said his attackers were aged 15 or 16. The boy got up after the attack and ran for help to a nearby shop. He was taken to Cheltenham General Hospital where he was given anti-infection treatment and blood tests.
Yesterday police spokeswoman Annabel Brittain issued a description of the two teenagers they believe carried out the attack.
The teenager who held him down was wearing a blue or black Adidas hooded top and is said to have curly blonde hair which was sticking out from the hood.
He was also wearing Reebok Classic trainers. The other attacker was wearing a black, possibly Umbro, tracksuit top.