Facebook users who were in Paris during the Friday night terror attacks were able to notify friends and family that they were safe through the site’s “Safety Check” tool.

Users began getting notifications that friends who were in Paris were safe on Friday evening as those in the area were able to check in.

The “Safety Check” tool was launched in 2014 and has been used five times. This is the first time the feature has been used in a non-natural disaster setting.

“We are shocked and saddened by the events unfolding in Paris. Communication is critical in these moments both for people there and for their friends and families anxious for news,” Facebook said in a statement.

“People turn to Facebook to check on loved ones and get updates which is why we created Safety Check and why we have activated it today for people in Paris,” Facebook added.

A Facebook spokeswoman told CNNMoney that the site did not immediately have the numbers to share on how many were marked safe in Paris due to the feature just being activated.

When first launched, Facebook noted that “Safety Check” would help users let friends and family know they are safe, check on others in the area, and mark friends as safe.

Facebook determines the location of a user in the area by “looking at the city you have listed in your profile, your last location if you’ve opted in to the Nearby Friends product, and the city where you are using the internet,” according to its site.

Source: CNNMoney