Facebook has activated its "safety check" system to help people check on friends and loved ones in the aftermath of the attacks in Brussels.
Related: Deadly blasts hit Brussels airport in terror attacks
The check-in system was put in use within hours of the three explosions at the Brussels airport and a metro station.
Facebook says the system can provide an easy way for people to mark themselves as "safe" after a major disaster or crisis so that people searching for them will know they are unharmed.
The check-in system has been used recently to help people communicate after the Paris attacks, major floods and earthquakes.
AP contributed to this report.