Four people have been treated in hospital for "burns, smoke inhalation and shock" following a fire at a flat in north Belfast.
The incident at a residential building in Flax Street was reported shortly before 05:30 GMT on Sunday.
The NI Fire Service said they "quickly rescued two people with an aerial appliance" and a further two people managed to self-rescue.
Eight other people were moved from the building by firefighters.
The firefighters extinguished the fire.
The NI Fire Service said at this stage "the fire is believed to have been caused by a mobile device being left on charge overnight, however further investigation will take place".