At least 50 people have died and more than 400 have been hospitalised after a gunman opened fire on crowds at a country music festival in Las Vegas, Nevada.
The gunman has been identified by authorities as Stephen Paddock of Nevada, who reportedly died at the scene.
Police said they found numerous weapons in his hotel room on the 32nd floor of the Mandalay Bay hotel.
President Donald Trump tweeted his "warmest condolences" the morning following the violent attack, and later spoke from the White House.
The attack, and Mr. Trump's response come two years to the day that former President Barack Obama gave a powerful, important and heartbreaking speech following a shooting in Oregon.
Mr. Obama was visibly upset in the press briefing room that day and said:
Somehow this has become routine. The reporting is routine. My response here at this podium ends up being routine, the conversation in the aftermath of it ... We have become numb to this.
I would ask the American people to think about how they can get our government to change these laws and to save lives, and to let young people grow up. That will require a change of politics on this issue,” he said. “If you think this is a problem then you should expect your elected officials to reflect your views.
Mr Trump made no references to gun control in his speech today, instead choosing to focus on faith, he said:
Scripture teaches us, “The Lord is close to the brokenhearted and saves those who are crushed in spirit.” We seek comfort in those words, for we know that God lives in the hearts of those who grieve. To the wounded who are now recovering in hospitals, we are praying for your full and speedy recovery, and pledge to you our support from this day forward.
In memory of the fallen, I have directed that our great flag be flown at half-staff.