World Bulletin / News Desk
More than 200 firefighters raced against time to tackle the fire which engulfed the 27-story Grenfell Tower, near Kensington.
Commander Stuart Cundy, from the Metropolitan Police, confirmed at least six deaths but said this figure was likely to rise.
A “complex recovery operation” was expected over the next few days, he added.
The fire started at around 1 a.m. local time and is believed to have taken hold of the whole building, which contained 120 apartments.
“It is likely to take some time before we are in a position to confirm the identity of the victims and it is too early to speculate on the cause of the fire,” the Metropolitan Police added.
Describing the fire earlier as “an unprecedented incident,” London Fire Commissioner Dany Cotton said: “In my 29 years of being a firefighter, I have never ever seen anything on this scale.”
Emergency services said more than 50 people were in various hospitals and some of were in critical condition with serious burns and smoke poisoning.
A search-and-rescue operation is ongoing as the fire has been partly brought under control.
Mayor of London Sadiq Khan said hundreds members of the emergency services were dealing with the situation, and described the fire as a "major incident".
The area has been cordoned off and adjacent properties evacuated.