A teenage girl was taken to hospital with her skin peeling off her face after being attacked with pepper spray in her school playground.
Two teenage girls were arrested after the alleged attack at Beaverwood School for Girls in Chislehurst, Kent.
Police said the 14-year-old victim had been allegedly sprayed in the face with an 'unknown substance' and required medical attention.
They said two girls aged 13 and 14 had been arrested on suspicion of possessing a prohibited weapon and released on bail.
Robbie Nicolson, 43, an uncle of one of the victims, told how one of the attackers 'went on a rampage'.
He said: "The girls were in the school playground and one girl has gone round spraying nine other girls in the face. When my niece's mum found out she went straight down there.
"There was skin peeling off her face. She was taken to Queen Mary's Hospital."
Another parent, who asked not to be named, told the Evening Standard: "I got a call from my daughter saying there had been an attack in the playground and that some girls had been sprayed in the face with pepper spray.
"They were in agony and some of them thought they had been blinded."
A spokeswoman for the school said: "Beaverwood School for Girls is proud of the calm and sensible way in which yesterday's isolated incident was dealt with by students and staff. It is business as usual for the school community as exams are underway.
"At break time, a teenager randomly sprayed a can, the unidentified contents of which accidentally caught some of her friends. Only one student was treated in hospital. No other students were involved.
"The school continues to take all appropriate actions."