West Yorkshire Fire Service investigators are now working in the eighth-floor flat in Poplar Court to determine the cause of this morning's blaze.
The investigation team said in a statement on Twitter that due to the severity of the fire, their officers are finding examination of the scene 'difficult'.
A spokesman for the service said on Twitter: "Fire at Bramley Leeds today started in a bedroom on the 8th floor.
"Due to the severity of the fire and the room being totally destroyed, an investigation into the cause is proving difficult."
Six fire engines were originally sent to the block, but the fire was quickly brought under control. Three people were taken to hospital as a precaution.
Residents from the floors above the affected flat were evacuated.
Some claimed that they had not heard a fire alarm to alert them to the danger.
“There were no alarms going off. It’s scary because Grenfell was just eight months ago. We need alarms and we need a sprinkler system.”
Oksana Dovgan, 35, said the first she knew of the fire was when a friend a neighbouring block of flats called to alert her.
“She rang me and said ‘Where are you?’ I said I was at home so she said ‘you need to get out, I can see there’s a fire at your home’.
“She had seen the fire engines. I heard no alarm and I didn’t smell anything.”
She added: “When I came outside and could smell smoke, I realised it was more serious than I was expecting.”
Occupants have now been allowed back into the building.