The fire department earlier said five of the injured were in critical condition and that several residents were hanging out of windows as firefighters arrived. Some jumped and were injured, the department said.
The fire was in the first-floor unit of the Alpine Motel Apartments, and its cause was under investigation, the department said.
Ten ambulances were called to the scene after the blaze was reported about 4 a.m., Fire & Rescue spokesman Tim Szymanski told Fox 5 in Las Vegas, and five more rescue services were requested. Ladder evacuations were conducted quickly because of jumpers, and firefighters saw sheets hanging from windows that occupants had tried to use to escape the flames, the outlet reported.
Homicide and coroner investigators were at the scene, but that is standard for fatal fires in Las Vegas, the fire department said.
Officials said that 23 people were displaced, and the Southern Nevada Red Cross said it sent personnel to provide assistance.
No firefighters were injured.