Updated

Arson investigators are probing a fire that broke out in a guest room on the unoccupied 22nd floor of the Golden Nugget hotel in downtown Las Vegas.

One man was found unconscious in the room and was taken to a hospital in critical condition shortly after firefighters responded at about 8:30 a.m. Thursday.

The 22nd floor is one of several undergoing renovations in the hotel's Rush Tower. Las Vegas fire department spokesman Tim Szymanski says it's not clear whether the man was a worker.

Golden Nugget spokeswoman Amy Chasey says about 60 people were evacuated from the hotel's 21st floor, and nine were evacuated from suites on the hotel's top floor, the 25th. Three floors in between are unoccupied.

Officials say sprinklers helped control the fire.