Facebook has launched a new feature in the UK to offer support to users who may be suicidal.
The Suicide Prevention tool was developed alongside members of the charity Samaritans.
Users are asked by the tool to flag or report posts from friends that may cause concern.
These are then reviewed by a special team at the social network, with help options sent to those the reviewers deem to be struggling.
A message appears when the person in question next logs in that reads: "Hi, a friend thinks you might be going through something difficult and asked us to look at your recent post."
They can then choose to talk to someone - either a friend or helpline worker, or be sent tips and support directly. There is also an option to ignore the offers altogether.
Facebook's safety policy manager in the UK, Julie de Bailliencourt, said: "Keeping the Facebook community safe is our most important responsibility.
"We worked with organisations including Samaritans to develop these tools, and one of the first things they told us was how much connecting with people who care can help those who are struggling to cope - whether offline or online.
"People use Facebook to connect with friends and family, and that's why we're evolving the support, resources and advice available to people who are in distress and their concerned friends and family members."