Experts are warning of a convincing Facebook Messenger scam that looks as if a friend has sent through a video link.
The malware is said to have "the potential to do huge damage" if the link tricks users into clicking into the external site and installing the application.
The scam appears as if a Facebook friend has sent a message along the lines of: "You are in this video?"
There is usually an emoji after the message and a link to an external site appearing like a YouTube link.
But instead of directing the victim to a video, it goes to a different page and prompts the user to install an app to view the clip.
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"Once that happens, the virus is on your machine, goes back into Facebook and sends the virus to all your friends, so you need to watch your posts to see if you have been infected," Val Quinn from from Gadget Guy said.
Mr Quinn said the scam is "sneaky" as it comes in a range of languages.
For those who have accidentally clicked on the link, experts have advised Facebook users to change their password immediately.
Then, victims should let their friends know the link is malware and disable any applications on their phone they do not recognise.