Official sources revealed that a gunman identified as 64-year-old Stephen Paddock opened fire from the 32nd floor of the Mandalay Bay Hotel towards an open-air music festival.
Paddock was shot dead by officers in the hotel where several guns were also found.
President Donald Trump expressed his "warmest condolences and sympathies" to the victims and their families, and said the shooting was "terrible".
Speaking to the press, Sheriff Joe Lombardo described the events as a “lone wolf” attack. He confirmed that two off-duty police officers were among the fatal victims, and said the police was seeking “a companion” named Marilou Danley. Authorities later stated they were “confident” they had located her.