Six people were killed and 13 injured after a fire Saturday morning in a three-story apartment complex in downtown Las Vegas, authorities said.

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. Several jumped and were injured, the department said.

8AM UPDATE: All agencies, @LasVegasFD Fire Investigators, @LVMPD Homicide & CSI & @CCCoroner investigators on scene investigating incident, this is STANDARD PROCEDURE for any fatal fire in @CityOfLasVegas. Total numbers now 5 fatalities, 13 injured, @RedCrossUtahNV 23 displaced. pic.twitter.com/2IFDf54z2D — Las Vegas FireRescue (@LasVegasFD) December 21, 2019

The fire was in first-floor unit of the Alpine Motel Apartments and its cause was under investigation, the department said. A fire official said it appears to have been accidental.

Homicide and coroner investigators were at the scene but that is standard for fatal fires in Las Vegas, the fire department said.

The department said 30-35 people were displaced and the Southern Nevada Red Cross said it sent personnel to provide assistance.

No firefighters were injured.