Trapped and injured construction workers could be heard crying out for help as rescue teams navigated smoke and dust to locate them.
One person was killed and at least 18 were injured after the Hard Rock Hotel in New Orleans collapsed on Saturday, authorities said.
The hotel, which is under construction, began to shake just after 0912 (1412 GMT), local media reported. Seconds later, construction crew members inside said they saw parts of the floor give way.
At least three people are unaccounted for, Governor John Bel Edwards said.
Compounding concerns for authorities is the fact that a crane positioned near the damaged side of the building could come crashing down.