Facebook activated its first Safety Check in the United States after a gunman massacred at least 50 people at a gay nightclub in Orlando, Florida, early Sunday in the deadliest mass-shooting in American history.

The feature allows Facebook users to confirm they are safe if they are near the scene of a mass shooting or another deadly situation. Facebook activated Safety Check after an extremist attack in Paris in November, after an overpass collapse in Kolkata, India, in March, and in other similar situations.

"Earlier this month, we began testing features that allow people to both initiate and share Safety Check on Facebook," a Facebook spokesperson said in a statement provided to Mashable. "Over the last few months, we have improved the launch process to make it easier for our team to activate more frequently and faster, while testing ways to empower people to identify and elevate local crises as well.”

The social network mistakenly sent out a Safety Check alert to U.S. users following an explosion in Pakistan earlier this year. That alert was sent in error.

After deploying the feature on Sunday, the spokesperson said Facebook hopes "the people in the area find the tool a helpful way to let their friends and family know they're okay."

The tool can be useful for families and friends to determine whether loved ones are safe in the hours after a disaster when authorities have not yet identified the names of those who have died. Officials in Orlando are still working to identify victims of the shooter.

Various media outlets have reported that the shooter as a man named Omar Mateen, who was fatally shot by police after what they called a well-organized attack.

Officials are investigating whether the shooter had ties to any larger organization.

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