(CNN) — A partial collapse of a building under construction in New Orleans has killed one person, injured more than a dozen others and left at least three people missing, authorities said.

At around 10:15 am ET, the upper three floors of the building collapsed, according to Tim McConnell, New Orleans Fire Department Superintendent.
The building is a Hard Rock Hotel construction site, according to CNN affiliate WDSU.
"The building is unstable so a collapse is still possible — further collapse of the building," McConnell said. 
Authorities say 18 people were injured. Several people taken to University Medical Center are in critical condition, said Royce Duplessis, a Louisiana State Representative who is on the scene.
McConnell added that three people believed to be in the area of the building when it collapsed have not been located.