China has launched an app that allows people to check whether they have been at risk of catching the coronavirus.
The 'close contact detector' tells users if they have been near a person who has been confirmed or suspected of having the virus.
People identified as being at risk are advised to stay at home and inform local health authorities.
The technology shines a light on the Chinese government's close surveillance of its population.
To make an inquiry users scan a Quick Response (QR) code on their smartphones using apps like the payment service Alipay or social media platform WeChat.
Once the new app is registered with a phone number, users are asked to enter their name and ID number. Every registered phone number can then be used to check the status of up to three ID numbers.