A Tinder-like app popular among teenagers and young adults has allegedly been used to extort users by tricking them into sending sexually explicit photos, a problem that internet safety watchdogs say is indicative of the challenges of keeping young people safe on social media.

The app, Wizz, allows users to scroll through profiles that show a person’s picture, first name, age, state and zodiac sign. Wizz advertises the app as a “safe space” to meet new friends and allows users as young as