Apple has said children should not use the new iPhone’s facial recognition technology, saying faces of under-13s could be too similar to each other to protect phones from intruders.

The iPhone X, which is set to go on sale next month, uses a facial recognition system called Face ID to unlock phones, verify payments and gain access to apps. It has an array of sensors at the top of the phone that scan the users’ face and compare it to the model stored on the phone.

Apple says the chances of an imposter being able to trick the system are one in a million, making facial recognition more secure than the one in 50,000 chance that somebody else could fool a phone’s fingerprint scanner.