Police have warned parents and children of a Facebook scam involving fake modelling agencies.
Leicestershire Constabulary said the scam, using a number of social networking sites, appears to involve the fake agencies encouraging children to pose in their underwear.
The force said it seemed a number of false Facebook profiles had been set up posing as modelling agencies, even using agency logos to appear genuine.
They then contact children via email asking them if they are interested in modelling. After a series of emails, the children are pressurised into sending photographs of themselves in their underwear.
The force said it was investigating reports from concerned parents. The modelling agencies appear to be Leicester-based, the force said. The most recent used is the Pat Keeling Modelling Agency.
Police are working with Facebook for this particular site to be removed but new sites may continue to be set up. Pat Keeling Modelling Agency does not have a Facebook site and has pointed this out on its own genuine website.
Detective Sergeant Ed Jones, from Leicestershire Constabulary's paedophile and online investigation team, said: "Do not be fooled by these emails, a reputable modelling agency would never approach you in this way. Do not post pictures online of yourself posing in your underwear and if you are under 18 these photographs may be indecent under UK law.
"You have no control when posting photos on the internet where they may end up and they could appear on the internet forever. If you do find yourself in a situation of this nature online you can use the CEOP Report Abuse Button which is now available as an app on Facebook or contact police."
A Facebook spokeswoman confirmed staff are working in partnership with the police in Leicestershire and added: "The safety of the people who use Facebook is our top priority. Unfortunately there will always be malicious people who try to fool people, both online and offline. Just as you should check if someone 'scouting' you in a shopping centre really is a legitimate model agent you should also use the same caution on Facebook.
"We encourage people using Facebook to think carefully before they add a new friend and check that the person is who they claim to be and not to add or accept friend requests from people they don't know. It's against Facebook's rules to use a fake name or operate under a false identity. We provide our users with the tools to report anyone they think is doing this via report links on every page of our site and we strongly recommend their use."