The bodies of the remaining 11 victims are still inside the smouldering tower. (Photo: AP)
The blaze in west London's North Kensington district also injured 74 others, 18 of them critically, and left an unknown number missing.
Emergency supplies were offered to victims who managed to make it out of the building. People living around Grenfell tower helped those affected in the incident.
Up to 600 people lived in the 120 apartments at Grenfell Tower. After announcing the updated death toll of 12 on Wednesday afternoon, Cmdr. Stuart Cundy said that 'we believe this number will sadly increase.'
According to an emergency services officer, It is unsafe for firefighters to go to all parts of the 24-story tower, so the fire department is working with structural engineers to shore up the building so they can complete a 'finger-tip search' of the entire structure.
Local residents had warned a year ago about a potential fire risk caused by rubbish being allowed to accumulate during improvement works. \"This matter is of particular concern as there is only one entry and exit to Grenfell Tower during the improvement works,\" read a blog post by the Grenfell Action Group.
Large pieces of debris could be seen falling from Grenfell Tower, a 1970s block in the working-class north Kensington area - a short distance from chic Notting Hill. Frantic families at the scene attempted to call their loved ones, fearing they could be stuck inside, and were being directed by police to a nearby restaurant where some of the injured were being treated.
Witnesses said they heard screaming from the upper floors as the flames rose in the night and one desperate resident could be seen waving a white cloth from a top floor window. A London Underground line passing the area near Latimer Road station was also shut down.
Police said in a statement they were called at 1:16 am British time (0016 GMT) 'to reports of a large fire at a block of flats in the Lancaster West Estate'.
London mayor Sadiq Khan also declared it a 'major incident'.