Worried friends and family turned to social media to see if loved ones were caught up in the barrage of attacks in Paris that forced the area into a state of emergency. Others used social networks to show solidarity with France.
Knowing the frantic concern people were feeling for those in the city, Facebook enabled its safety check feature, its CEO said Friday.
Facebook users in Paris can mark themselves as safe, and the app notifies their friends on the site. The feature also allows friends who have made contact with the person to mark him or her as safe.
"My thoughts are with everyone in Paris tonight. Violence like this has no place in any city or country in the world," CEO Mark Zuckerberg said in a Facebook post on Friday announcing the change.
On Saturday, the social network launched a feature that would apply a French flag filter to a user's profile picture, so Facebook users can show solidarity with victim's of the terrorist attack with a red, white and blue profile pic. "We stand together. #JeSuisParis," Facebook wrote in the post introducing the feature.
The Safety Check feature is typically used during natural disasters like September's Chilean earthquake.
At least 129 people died Friday in shootings and explosions at multiple sites throughout Paris, French officials said. Eighty-nine people were killed inside the Bataclan concert hall alone, where Southern California band Eagles of Death Metal was playing a sold-out show.
Americans were among the 352 wounded, the State Department said. French President Francois Hollande vowed a "merciless" response against the perpetrators, as ISIS claimed responsibility.
Eight attackers targeted at least six locations in the French capital, authorities said. Police said they killed one of the terrorists and the others blew themselves up.
Many in Paris posted to their Facebook, Twitter or Instagram profiles to spread the word that they were not among those killed or wounded in the devastating attacks.
San Diego resident Caroline Farwell said she let her loved ones know she was OK through the social medium What'sApp.
As she and her friends walked along the Paris streets Friday evening, they heard about the attacks and ran into the lobby of a nearby hotel.
They waited there until it was safe enough for them to return to their rented apartment, she said.
"We're just sitting here trying to get new information. They don't have a TV in the lobby. The Internet is down. They won't let us use an access code," Farwell said. "So we're kind of just waiting for people that we know to call us or tell us or email us that the police reports are to stay inside."
Despite the terrifying experience, Farwell said everyone around her is doing a good job of staying calm.
Around the world, social media has been flooded with offerings of love, support, thoughts and prayers for everyone touched by the violence.
People in the U.S. looking to contact their friends and loved ones in France are also getting some help from Verizon. The company is offering free calling from the U.S. to France for it's customers through the weekend.