One person has died and three people are missing after a Hard Rock hotel building under construction suddenly collapsed.

Construction workers reportedly had to run for safety in New Orleans on Saturday as part of the building, which has been under construction for several months, came crashing down.

New Orleans Fire Department superintendent Tim McConnell said there has been one confirmed fatality, and people are still missing inside the building.

Authorities say 18 people were also taken to a hospital for treatment after being injured, but all were considered to be stable.

Mr McConnell said the upper six to eight floors of the building collapsed shortly after 9am.

New Orleans' Hard Rock Casino hotel collapses during construction Show all 9 1 /9 New Orleans' Hard Rock Casino hotel collapses during construction New Orleans' Hard Rock Casino hotel collapses during construction Construction workers look on after a large portion of the Hard Rock Casino hotel under construction in New Orleans suddenly collapsed on 12 October 2019. At least one person has died, three are still missing and about 18 have been injured after the upper six to eight floors came crashing down at about 9am local time. Scott Threlkeld/The Advocate via AP New Orleans' Hard Rock Casino hotel collapses during construction Emergency services help workers. Scott Threlkeld/The Advocate via AP New Orleans' Hard Rock Casino hotel collapses during construction Construction workers are helped by emergency personnel. Scott Threlkeld/The Advocate via AP New Orleans' Hard Rock Casino hotel collapses during construction Debris hangs off the side of the building after the collapse. Scott Threlkeld/The Advocate via AP New Orleans' Hard Rock Casino hotel collapses during construction At least one person has died and three are still missing after the upper floors of the Hard Rock Casino hotel collapsed during construction in New Orleans, 12 October 2019. New Orleans Fire Department New Orleans' Hard Rock Casino hotel collapses during construction At least one person has died and three are still missing after the upper floors of the Hard Rock Casino hotel collapsed during construction in New Orleans, 12 October 2019. New Orleans Fire Department New Orleans' Hard Rock Casino hotel collapses during construction At least one person has died and three are still missing after the upper floors of the Hard Rock Casino hotel collapsed during construction in New Orleans, 12 October 2019. New Orleans Fire Department New Orleans' Hard Rock Casino hotel collapses during construction At least one person has died and three are still missing after the upper floors of the Hard Rock Casino hotel collapsed during construction in New Orleans, 12 October 2019. New Orleans Fire Department New Orleans' Hard Rock Casino hotel collapses during construction Part of the Hard Rock Casino hotel, which is under construction in New Orleans, collapsed on 12 October 2019. WWL-TV via AP

The structure is still unstable and buildings in the area have been evacuated, he added.

It is not yet known what caused the collapse.

Witnesses described hearing a rumble and seeing a huge cloud of dust as the building came down, according to The New Orleans Advocate.

One worker told the newspaper that about 45 people were working inside the building, although this has not been confirmed by authorities.

The hotel was scheduled to open in the spring.

In a statement, Hard Rock International said: “We want to extend our deepest sympathies to victims of this tragic incident in New Orleans and to their loved ones and friends.