Celebrities are responding to the tragic mass shooting in Las Vegas, which left at least 58 people dead and more than 500 injured on Sunday (Oct. 1), in what has been called the deadliest mass shooting in U.S. history.

The gunman, who’s been identified by police as 64-year-old Stephen Paddock of Mesquite, Nev., opened fire on a crowd of people who were gathered at the Route 91 Harvest Festival, from the 32nd floor of the Mandalay Bay Resort and Casino in the middle of country star Jason Aldean’s set.

Police found a deceased Paddock in his hotel room, where he also had at least 10 rifles. Officials believe that he killed himself prior to their arrival. He had no significant criminal history, according to The New York Times.

Despite initial speculations of multiple shooters, Sheriff Joseph Lombardo said that the Las Vegas Police Department believes Paddock was “a sole actor, a lone wolf-type actor.” The description has been criticized by many, including several stars, who believe this should be called an act of terrorism.

“My heart is breaking for Las Vegas,” tweeted Ariana Grande. “We need love, unity, peace, gun control & for people to look at this & call this what it is = terrorism.”

“This is terrorism plain and simple,” Lady Gaga also tweeted. “Terror bares no race, gender or religion. Democrats & Republicans please unite now #guncontrol.”

https://twitter.com/ArianaGrande/status/914886991459651589

Other stars also called this an act of terrorism, while mourning the lives that were lost in the heinous act. “Devastating – prayers to those affected by the senseless act of domestic terrorism in Las Vegas. My heart goes out to each of you,” tweeted Kelly Rowland.

“Saying a prayer for all the victims & their loved ones, also for the residents & visitors of Las Vegas,” wrote Rihanna. “This was a horrific act of terror!!”

Zendaya added: “There’s nothing I can tweet that will heal the heartache being felt today, but all my heart is with Las Vegas. This is domestic terrorism.”

Jennifer Lopez and Mariah Carey, who’ve become Las Vegas ambassadors with residencies in the city, also offered their thoughts on the devastating event.

“Horrified to hear about the shooting in #LasVegas,” wrote Mariah. “My thoughts are with the victims and their families. Praying for everyone’s safety.”

“I ❤️ Las Vegas…feeling so broken this morning,” she wrote, before sharing the locations of blood donation centers in the city.

Several other stars shared their condolences and prayers in the wake of the tragic evening, including The Weeknd, Chance the Rapper, Usher, Ciara, Fabolous, Monica, and Vic Mensa. See more thoughts and heartfelt messages from celebrities below.

https://twitter.com/VicMensa/status/914835664453193728