The Israel-developed Facebook app Safety Check helped users let friends and family know that they were safe following the deadly attacks in Belgium on Tuesday. At least 30 people were murdered and scores of others wounded in back-to-back bombings of the Brussels airport and subway.

The current version of the social network tool, which was also used during November’s terrorist attacks in Paris, was developed at the Tel Aviv headquarters of Facebook Israel.

Around 4.1 million people used the Safety Check app in Paris. The app was also used in Nepal after a deadly earthquake in April 2015.

In 2011, Facebook Japan introduced the prototype of Safety Check, called Disaster Message Board, after the earthquake and tsunami that year. The technology was then sent for full development to the Israeli R&D team.

“Facebook has become like a public square, used by over a billion people, so being able to leverage the platform to enable people to receive reassurance that their loved ones are safe is something we are very proud to be a part of,” Facebook Israel Director of Engineering Roi Tiger said at a press conference following the Paris attacks.

[Photo: wochit news / YouTube ]