A 12-year-old boy was robbed by two teenagers in a supermarket car park by the border of Hove and Portslade.
One of the teenagers threatened to hurt the 12-year-old if he did not give them his mobile phone.
The victim handed over his phone and the teenagers left.
The mugging took place in the car park of the Sainsbury’s in Benfield Valley in West Hove just after 4pm on Monday (29 July).
Sussex Police said that both of the muggers were black. One was wearing a red jacket and shorts. The other was wearing a white t-shirt and blue jeans.
Any witnesses or anyone with information about the robbery is asked to call Sussex Police on 101 or the independent charity Crimestoppers anonymously on 0800 555111.