Two children have been arrested after an altercation in a Superdrug store that has been widely shared on social media.
A video appears to show a black 15-year-old boy being restrained and handcuffed by two civilian security staff, with one kneeling across his legs.
Sussex Police said its officers were called to the shop in East Street in Chichester, West Sussex, shortly after 3.30pm on Wednesday to reports that a group of teenagers had become involved in an altercation.
A shop worker also reported being assaulted, officers said.
A 15-year-old boy, from Worthing, and a 16-year-old boy, from Chichester, were arrested on suspicion of assault.
The actions of the security staff and police have been criticised by some on social media.
Three teenagers had been detained by civilian security staff by the time police arrived, Sussex Police said, with two subsequently arrested.
Both boys are in custody and being supported by “appropriate adults”.
The force said it is looking into the full circumstances of what happened.
A Chichester District Council spokesperson said: “We have been made aware of an incident that took place in Chichester city today and we want to clarify that no Chichester District Council staff were involved.”
Superdrug tweeted: “An incident occurred today in our Chichester store between Chichester BID rangers and a group of young males they were monitoring.
“Unfortunately female staff were also assaulted. This is now a police matter and we are offering our full assistance to Sussex Police.”