"We need love, unity, peace, gun control & for people to look at this & call this what it is = terrorism," writes the singer on social media.
At least 50 are dead and over 400 injured after a gunman fired on attendees at the Route 91 Harvest Festival on Sunday night during Jason Aldean's performance.
"My heart is breaking for Las Vegas," Grande wrote on Twitter Monday morning. "We need love, unity, peace, gun control & for people to look at this & call this what it is = terrorism."
Braun posted a lengthy message on his social media accounts as well.
"I don't really have words this morning. I am deeply saddened. And as horrifying as it is to say I can't tell you I'm surprised," he wrote. "Our greatest challenges are ahead of us. What took place in Las Vegas last night should never happen. What took place in Manchester should never happen. What took place in Charlottesville should never happen. But they are all happening. And ALL of them are terrorist attacks. They all strike fear in our ability to live our lives. They all make us question taking our children, our friends, our loved ones ... to public events that are supposed to bring us joy... in fear of devastation."
"My heart breaks for all those affected in Las Vegas. Nothing we do can bring back your loved ones and I am so sorry. For those in the hospital recovering we are with you. Keep fighting. And for all of us ... who are we? What will we choose to do in response? Will we just instagram and move on? Will we think this is about a hashtag with the word #vegas in it? Or will we wait until the next one affects us?" he asked. "THIS ONE affects us. #LasVegas is ALL of us. This is an attack on your friends, your family, your kids, your way of life. So as we think about those lost and those hurt this morning ... what do you and I owe them?"
He went on to share a story of strength from the One Love Manchester concert.
"When I was in Manchester I witnessed something defiant. At the end of the One Love Manchester show ... only 2 weeks after the attack and less than 24 hours since the london attack... when the cameras were off ... the crowd of 55,000 brave souls started to sing," he explained. "They echoed the words 'Manchester we're strong, we're strong, we're strong. We'll keep singing our songs, our songs, our songs!' This repeated for 15 minutes as they exited. Defiance in the face of fear. Las Vegas we're strong. We're strong. We're strong. We'll keep singing our songs... Together."