A 12-year-old girl was robbed at knifepoint and punched in the head by a gang of up to seven young men.
The attack happened on Thursday evening outside Tesco in Ingleby Barwick, on Teesside, when she was approached by the group of men, aged 17 to 19.
A smaller number were involved in the confrontation when a knife was held to her face and her mobile phone stolen.
Three people have been arrested and released on bail by police investigating the attack.
Det Cons Mick Stokes of Cleveland Police said:¿ This was a vicious assault by a group of thugs which left this young girl traumatised.
"There were seven people in the group and we believe four were involved in the attack on the youngster."
Police particularly want to speak to one man, aged 18 to 19, who wore a thick gold chain around his neck.
He is 5ft 10ins, with medium-length brown hair.