Facebook’s photo-sharing app Moments will not be made available in Europe due to concerns about its use of facial recognition. The app, which allows users to share mobile-phone photos with friends without posting them publicly, was launched in the US this week. The Irish data regulator said that users must be given a choice about whether they want it, with an opt-in. Moments arranges the photos on someone’s mobile phone into groups, based on when they were taken. The facial recognition technology can identify Facebook friends to whom users can then forward the photos.