Two people died and one woman was taken to hospital after a fire broke out in a block of flats.
Some 50 firefighters battled the flames after the blaze took hold at a building in Deptford, south-east London.
A London Ambulance Service spokeswoman said: "Our staff treated a total of six patients on scene. Three patients were assessed but did not need hospital treatment and one patient, a woman, was taken to Lewisham Hospital suffering from smoke inhalation.
"Sadly two patients were confirmed dead at the scene despite extensive efforts to resuscitate them."
Emergency services were called to Marine Tower in Abinger Grove at about 2.45pm on Friday to tackle the blaze on the 15th floor.
Ten fire engines, seven ambulance crews and the air ambulance were among them. Police, who also attended the scene, said road closures were in place as crews dealt with the incident.
A London Fire Brigade spokesman said: "Part of the 15th floor of the block is alight.
"Six people were rescued from the building. Two were pronounced dead at the scene by London Ambulance Service. Four other people were treated at the scene, one of whom was taken to hospital.
"The cause of the fire is not known at this stage."
The two victims who died are understood to be adults.