Orlando triggers Facebook 'Safety Check' for first time in US

Before you go, we thought you'd like these...

Orlando Facebook

By Angela Moon

NEW YORK (Reuters) - Facebook Inc activated its "Safety Check" function on Sunday for the first time in the United States after a gunman massacred 50 people at a nightclub in Orlando, Florida.

The Safety Check, first introduced in October 2014, allows Facebook users to spread the word that they are safe in wake of a natural disaster or a crisis, and allows searches for those who might be in the affected area.

"Waking up this morning, I was horrified to hear about the shooting in Orlando. My thoughts and prayers are with the victims, their families and the LGBT community," said Facebook Chief Executive Mark Zuckerberg on his official account.

A gunman armed with an assault rifle killed 50 people at a packed gay nightclub in Orlando on Sunday in the worst mass shooting in U.S. history. Police killed the shooter at the Pulse nightclub, who was identified as Omar Mateen, a 29-year-old Florida resident and U.S. citizen.

The incident quickly emerged as a top trending topic on Facebook and Twitter with hashtag #PrayforOrlando being one of the top posts throughout the day.

Last year, Facebook vowed to turn on the Safety Check more often during disasters in response to criticism that it enabled the function after Islamic State militant attacks on Paris and not a day earlier when a bomb killed at least 43 people in Beirut.

(Editing By Frank McGurty and Alistair Bell)

Photo coverage of the Orlando shooting:

34 PHOTOS
Orlando Pulse Nightclub shooting
See Gallery
Orlando triggers Facebook 'Safety Check' for first time in US
Orlando Police officers direct family members away from a multiple shooting at a nightclub in Orlando, Fla., Sunday, June 12, 2016. A gunman opened fire at a nightclub in central Florida, and multiple people have been wounded, police said Sunday. (AP Photo/Phelan M. Ebenhack)
Brandon Shuford, left, waits down the street from the scene of a shooting involving multiple fatalities at a nightclub in Orlando, Fla., Sunday, June 12, 2016. (AP Photo/Phelan M. Ebenhack)
Bystanders wait down the street from a multiple shooting at the Pulse nightclub in Orlando, Fla., Sunday, June 12, 2016. A gunman opened fire at a nightclub in central Florida, and multiple people have been wounded, police said Sunday. (AP Photo/Phelan M. Ebenhack)
An aerial view shows the Pulse gay night club after a mass shooting in Orlando, Florida, U.S. June 12, 2016. REUTERS/Carlo Allegri
Friends and family members embrace outside the Orlando Police Headquarters during the investigation of a shooting at the Pulse nightclub, where people were killed by a gunman, in Orlando, Florida, U.S June 12, 2016. REUTERS/Steve Nesius TPX IMAGES OF THE DAY
Orlando Mayor Buddy Dyer, center right, and Orlando Police Chief John Mina, center left, arrive to a news conference after a fatal shooting at Pulse Orlando nightclub in Orlando, Fla., Sunday, June 12, 2016. (AP Photo/Phelan M. Ebenhack)
Friends and family members embrace outside the Orlando Police Headquarters during the investigation of a shooting at the Pulse nightclub, where people were killed by a gunman, in Orlando, Florida, U.S June 12, 2016. REUTERS/Steve Nesius
Friends and family members embrace outside the Orlando Police Headquarters during the investigation of a shooting at the Pulse nightclub, where people were killed by a gunman, in Orlando, Florida, U.S June 12, 2016. REUTERS/Steve Nesius
Jermaine Towns, left, and Brandon Shuford wait down the street from a multiple shooting at a nightclub in Orlando, Fla., Sunday, June 12, 2016. Towns said his brother was in the club at the time. A gunman opened fire at a nightclub in central Florida, and multiple people have been wounded, police said Sunday. (AP Photo/Phelan M. Ebenhack)
ORLANDO, FL - JUNE 12: FBI agents investigate near the damaged rear wall of the Pulse Nightclub where Omar Mateen allegedly killed at least 50 people on June 12, 2016 in Orlando, Florida. The mass shooting killed at least 50 people and injuring 53 others in what is the deadliest mass shooting in the country's history. (Photo by Joe Raedle/Getty Images)
ORLANDO, FL - JUNE 12: FBI agents investigate near the damaged rear wall of the Pulse Nightclub where Omar Mateen allegedly killed at least 50 people on June 12, 2016 in Orlando, Florida. The mass shooting killed at least 50 people and injuring 53 others in what is the deadliest mass shooting in the country's history. (Photo by Joe Raedle/Getty Images)
ORLANDO, FL - JUNE 12: FBI agents investigate near the damaged rear wall of the Pulse Nightclub where Omar Mateen allegedly killed at least 50 people on June 12, 2016 in Orlando, Florida. The mass shooting killed at least 50 people and injuring 53 others in what is the deadliest mass shooting in the country's history. (Photo by Joe Raedle/Getty Images)
Jermaine Towns, left, and Brandon Shuford wait down the street from a multiple shooting at a nightclub in Orlando, Fla., Sunday, June 12, 2016. Towns said his brother was in the club at the time. A gunman opened fire at a nightclub in central Florida, and multiple people have been wounded, police said Sunday. (AP Photo/Phelan M. Ebenhack)
Friends and family members embrace outside the Orlando Police Headquarters during the investigation of a shooting at the Pulse night club, where as many as 20 people have been injured after a gunman opened fire, in Orlando, Florida, U.S June 12, 2016. REUTERS/Steve Nesius TPX IMAGES OF THE DAY
Demetrice Naulings sobs outside the Orlando Police Headquarters where police are interviewing witnesses in the investigation of a shooting at the Pulse nightclub, where people were killed by a gunman, in Orlando, Florida, U.S June 12, 2016. REUTERS/Steve Nesius
Concerned friends and family of victims of the Pulse nightclub shooting wait outside of the Orlando Police Department on Sunday, June 12, 2016. (Joe Burbank/Orlando Sentinel/TNS via Getty Images)
Ray Rivera, DJ at the Pulse nightclub, is consoled by a friend outside of the Orlando Police Department on Sunday, June 12, 2016. (Joe Burbank/Orlando Sentinel/TNS via Getty Images)
FBI assistant special agent in charge Ron Hopper, center, answers questions from members of the media after a fatal shooting at Pulse Orlando nightclub in Orlando, Fla., Sunday, June 12, 2016. Listening are Orlando Police Chief John Mina, left, and Orange County Mayor Teresa Jacobs. (AP Photo/Phelan M. Ebenhack)
Police stand in front of one of the houses that officials indicated was connected to the Orlando shooter in Port St. Lucie, Florida, U.S. June 12, 2016. REUTERS/Joe Skipper
An aerial view shows the Pulse gay night club after a mass shooting in Orlando, Florida, U.S. June 12, 2016. REUTERS/Carlo Allegri
Police stand in front of one of the houses that officials indicated was connected to the Orlando shooter in Port St. Lucie, Florida, U.S. June 12, 2016. REUTERS/Joe Skipper
ORLANDO, FL - JUNE 12: FBI agents investigate near the damaged rear wall of the Pulse Nightclub where Omar Mateen allegedly killed at least 50 people on June 12, 2016 in Orlando, Florida. The mass shooting killed at least 50 people and injuring 53 others in what is the deadliest mass shooting in the country's history. (Photo by Joe Raedle/Getty Images)
ORLANDO, FL - JUNE 12: FBI agents investigate near the damaged rear wall of the Pulse Nightclub where Omar Mateen allegedly killed at least 50 people on June 12, 2016 in Orlando, Florida. The mass shooting killed at least 50 people and injuring 53 others in what is the deadliest mass shooting in the country's history. (Photo by Joe Raedle/Getty Images)
Officers arrive at the Orlando Police Headquarters during the investigation of a shooting at the Pulse nightclub, where people were killed by a gunman, in Orlando, Florida, U.S June 12, 2016. REUTERS/Steve Nesius
An aerial view shows the Pulse gay night club after a mass shooting in Orlando, Florida, U.S. June 12, 2016. REUTERS/Carlo Allegri
An Orange County Sheriff's Department SWAT member arrives to the scene of a fatal shooting at Pulse Orlando nightclub in Orlando, Fla., Sunday, June 12, 2016. (AP Photo/Phelan M. Ebenhack)
Orange County Sheriff's Department SWAT members arrive to a fatal shooting at Pulse Orlando nightclub in Orlando, Fla., Sunday, June 12, 2016. (AP Photo/Phelan M. Ebenhack)
Police cars and emergency vehicles surround the Pulse Orlando nightclub, the scene of a fatal shooting, in Orlando, Fla., Sunday, June 12, 2016. (AP Photo/Phelan M. Ebenhack)
A police officer stands guard outside the Orlando Regional Medical Center hospital after a fatal shooting at a nearby Pulse Orlando nightclub in Orlando, Fla., Sunday, June 12, 2016. (AP Photo/Phelan M. Ebenhack)
Emergency personnel wait with stretchers at the emergency entrance to Orlando Regional Medical Center hospital for the arrival of patients from the scene of a fatal shooting at Pulse Orlando nightclub in Orlando, Fla., Sunday, June 12, 2016. (AP Photo/Phelan M. Ebenhack)
Police cars surround the Pulse Orlando nightclub, the scene of a fatal shooting, in Orlando, Fla., Sunday, June 12, 2016. (AP Photo/Phelan M. Ebenhack)
Orlando Police Chief John Mina and other city officials answer the media's questions about the Pulse nightclub shooting in Orlando, Florida June 12, 2016. REUTERS/Kevin Kolczynski
Police lock down Orange Avenue around Pulse nightclub, where people were killed by a gunman in a shooting rampage in Orlando, Florida June 12, 2016. REUTERS/Kevin Kolczynski
of
SEE ALL
BACK TO SLIDE
SHOW CAPTION +
HIDE CAPTION

More on AOL.com:
Donald Trump says he told us so in anti-immigrant Orlando response
Orlando club owner opened Pulse to celebrate her brother who died of AIDS
ISIS claims responsibility for Orlando nightclub shooting
Read Full Story

People are Reading