The move is part of a drive to improve security on Facebook, and comes in the wake of password hacks at other networking sites including LinkedIn and eHarmony.

Millions of Facebook users have already seen a link at the top of their desktop news feed requesting them to follow “simple security tips”.

They are then requested to provide their phone number for secure account recovery.

The social network would then send a text message to the user informing that their password has been changed.

This, the site reasons, would be preferable to sending the user an email because many of these are ignored as assumed junk and get deleted.

Facebook on Friday said the desktop security message, already seen by millions of users in the US, will be on all accounts in the next few days.