Police in the North East have warned schools that an app dubbed Tinder for teens could be used by sex offenders to target children.
Yellow, which is available for free on the iPhone and Android, describes itself as the "easy and free way to make new friends" and uses swipe controls identical to that of dating app Tinder.
Users can swipe right and left to match with others and then exchange messages and photos with them.
Northumbria Police have alerted local schools to concerns they have over child safety on the app - aimed at teenagers - as users do not have to verify their age before using the service, raising concerns it could be exploited by adults pretending to be children.
Castletown Primary School in Sunderland said in a message to parents: "We have been informed by Northumbria Police about an app called 'Yellow' which is available on both iPhone and Android. It is basically a dating app for children.
"If anyone knows of 'Tinder', it is essentially the same, allowing young people to find others nearby and send photos of themselves. It is very easy for adults to use the app, posing as a young person," the school wrote on its Facebook page.
Yellow's guidelines do not permit users under the age of 13 on the app, while it says those aged between 13 and 17 must have parental permission to create a profile.
Those who register as over the age of 18 are also blocked from contacting younger users, however the app does not verify ages upon sign-up, leading to fears that it could be exploited by those seeking to target children.
Following concerns raised by online safety groups after the app was launched last year, Yellow has updated its security settings so that users who attempt to change their date of birth after signing up now have to send proof of ID to the app in order to verify the change.
Profile pictures that do not contain faces are now also banned from the app.
Northumbria Police neighbourhood inspector Don Wade said: "The advice was given as part of an input by local neighbourhood officers who visited the school to speak to the school children about a range of issues including online safety.
"It was given as general information around the social media sites that exist and not in response to any particular concerns that have been raised."
Coun Louise Farthing, Portfolio Holder for Children’s Services, Sunderland City Council, said: "Keeping our children informed of online safety issues is hugely important and something for which we’re all responsible. Children and their parents alike need to be aware of the risks around digital media, particularly as new social networking sites arrive so often.
"With this in mind, we provide parents and schools with cyber safety information booklets and cyber safety features high on the agenda at our regular anti-bullying conferences for partners and professionals. All schools also have a designated staff member who is trained each term around safeguarding.
"We will continue to work closely with partners, including police and schools to update families on the latest safety issues, including social media sites and the potential risks that they could pose."