Police investigating a school football coach who faces a string of charges of sexual offences against children say they are now trying to trace 250 children.
Jonathan Clarke has admitted seven charges already, including making more than 150 indecent images and videos of children.
The 31-year-old of Highview Close, Blofield, in Norfolk, was arrested in January after police were alerted to a social media account.
He had worked as a football coach at two schools in Norfolk as well as a youth football team.
Clarke appeared at Norwich Crown Court on Tuesday and admitted seven charges including encouraging a girl aged 11 to engage in sexual activity and getting a 12-year-old girl to remove her clothes on a video call.
He also pleaded guilty to making 36 category A, 12 category B and 117 category C indecent images and videos of children.
Norfolk Police said that the investigation was continuing, and that officers were trying to identify and trace some 250 children.
It is understood that the process could take several weeks.
Clarke also faces two charges related to a 10-year-old girl, including inciting her to engage in sexual activity and blackmailing her into sending him images. He has yet to enter a plea on those charges.
He has been remanded in custody with a further hearing due later this month.