Multiple victims have been taken to hospital after a shooting at a music festival on the Las Vegas Strip.
Dozens of patrol vehicles descended on the Strip after authorities received reports of an active gunman near the Route 91 Harvest Festival.
Some officers took cover behind their vehicles while others carrying assault rifles ran into the Mandalay Bay Hotel and Casino.
University Medical Centre spokeswoman Danita Cohen said the hospital was taking in "several" people with gunshot wounds. She did not have any other details.
Authorities shut down part of the Las Vegas Strip and Interstate 15.
Some flights destined for McCarran International Airport were diverted due to the incident.
Witnesses said country singer Jason Aldean was playing near the end of the concert when gunfire rang out.
No further information was immediately known.