The number of people confirmed dead after the Grenfell Tower fire in west London has risen to 17.
"We do believe that that number will sadly increase," Met Police Commander Stuart Cundy said.
Earlier, London Fire Commissioner Dany Cotton said there were still "unknown numbers of people" inside the block.
Many people from the 120 flats remain missing, with relatives and friends desperately appealing for information.
In another update on Thursday morning, NHS England said 37 people were still being treated in hospital, 17 of them in a critical condition.
Firefighters are working their way through the smouldering remains of the building's 24 floors.
Specially trained dogs are being sent in to look for victims. Ms Cotton said the "benefit" of using the animals was that they were "much lighter than people and they can cover a greater area in a very short space of time".
Ms Cotton said that because of the "severity of the fire", it would take a "long time" to search the tower "to properly identify anyone who is left in the building".
The "core" of the building is "structurally sound at the moment", she said, adding that the upper floors would be "more challenging".
Because of the size of the building, she said the operation could take "weeks".
"Tragically," she added, "we are not expecting to find anyone else alive. The severity and the heat of the fire will mean that it would be an absolute miracle for anyone to be left alive."
Ms Cotton said the fire was now "out". "There will be still some smoke but the fire is out," she told Sky News.
The scene is "unparalleled" when compared to anything she has witnessed before in her 29 years as a firefighter.
"I've truly never seen that in a high-rise building," she said.
Even though the building was "alight from top to bottom", Ms Cotton said her crews, who were "in fear of their own lives", were "very committed" and had done "absolutely sterling work".
But "going forward", she worries about the "psychological effect".
"A lot of my firefighters experienced things they will never have seen before, and I spoke to some people who were truly distressed.
"Not least of all because they knew there were people still in there and they were battling through the heat and couldn't get there."
Witnesses of Wednesday's disaster said some people jumped from their flats, while others saw babies and children being dropped into the arms of people below.
Ms Cotton said she had spoken to one of her officers who was "very near when someone came out the window".
"He was in tears," she said. "He's a professional fire officer. We like to think of ourselves as rufty-tufty and heroes. They are heroes, but they have feelings, and people were absolutely devastated by yesterday's events."
London Fire Brigade said it had rescued 65 people and that firefighters managed to battle all the way to the top floor.
The tower, built in 1974, was home to between 400 and 600 people.
Concerns are most acute for those who lived on the hard-to-reach upper floors, with one woman posting a harrowing video of herself screaming for help as smoke closed in.
The Queen has said her "thoughts and prayers are with those families who have lost loved ones".
"Prince Philip and I would like to pay tribute to the bravery of firefighters and other emergency services officers who put their own lives at risk to save others," Her Majesty said.
"It is also heartening to see the incredible generosity of community volunteers rallying to help those affected by this terrible event."
Kensington Palace has announced that the Duke and Duchess of Cambridge and Prince Harry will be making a donation to the London Evening Standard newspaper's emergency appeal.
A spokesman said: "The tragedy at Grenfell Tower has left a number of local people in need of urgent assistance.
"The Duke and Duchess of Cambridge and Prince Harry are pleased the Evening Standard's Dispossessed Fund has immediately swung into action.
"As residents of the local area they are keen to offer their immediate support."
Theresa May, who visited the scene on Thursday morning, has promised a "proper investigation" after witnesses said the flames surged from the lower floors and engulfed the tower in under an hour.
"When it's possible to identify the cause of this fire, then of course there will be proper investigation and if there are any lessons to be learnt they will be, and action will be taken," the Prime Minister said.
Labour leader Jeremy Corbyn has also visited the scene.
Angry locals have pointed the finger at cladding that was added to the outside last year as part of an £8.6m refurbishment.
Residents' groups said they had raised "numerous warnings" about the tower's safety, while people who escaped complained fire alarms did not go off and criticised advice that told them to stay in their flats.
Grenfell Action Group posted in their blog in November that "only a catastrophic event" would expose the "ineptitude and incompetence of our landlord".
It said there was only one entry and exit during improvement works and that there were exposed gas pipes weeks before the fire.
Rydon, the firm that carried out the work, said in a statement that the project "met all required building regulations".
However, a line from an earlier statement saying that it complied with all "fire regulation and health and safety standards" was left out.
Barrister Jolyon Maugham QC wrote on Twitter: "If residents of Grenfell Tower want legal help with compensation and responsibility many lawyers will be happy to help. For free. I will."
Amid the devastation, many have praised the way the community has pulled together to help those who escaped the building with only the clothes they were wearing.
Community centres, churches and mosques in the area say they have been inundated with donations of food, water and clothing.
Kensington and Chelsea council said emergency accommodation had been provided to 44 households so far.
Others, left homeless, have been staying at the nearby Westway Sports Centre and other rest centres.
Local football clubs Queens Park Rangers and Fulham have also opened their doors and are helping to collect donations.
Some people have being posting on social media to offer transport or a place to stay. Crowdfunding pages have also raised more than £1m in less than 24 hours.
As the focus moves to how the fire started and why it spread so quickly, policing and fire minister Nick Hurd said emergency checks would be carried out on tower blocks undergoing similar renovations. (Sky News)
