Facebook have this morning turned on their Safety Check feature following the terrorist attacks in Brussels.
The Safety Check feature, available here, allows people to check on their friends and family in the area who use the social media site.
People can mark themselves as safe, or people they know and who know their whereabouts can list them as safe.
The feature, originally used for natural disasters, was turned on in the wake of the Paris attacks in November last year.
It has also been used following terrorist incidents in Nigeria and Turkey.