"Sadly I can confirm that the number of people that have died is now 17", London police commander Stuart Cundy told reporters. Fire Commissioner Dany Cotton says specialist dogs would start searching the 24-story building.
Multiple residents told CNN they did not hear fire alarms when the blaze broke out.
A day after the giant fire at London's Grenfell Tower, the local fire chief said that judging by the severity of the blaze, it would be a "miracle" to find survivors trapped in the building.
"We are urging members of the public that wish to make donations to check that they give to a registered charity in order to best support those affected, and also importantly to check with those charities what support they need - whether that is money, time or other essential supplies".
The queen says "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".
It added: "There have been few recorded incidents of serious fire spread involving external cladding, and, although in our view any loss of life in incidents such as these should be prevented if at all possible, neither have there been many deaths".
Cotton says that firefighters are having trouble with the aftermath. "We need to know what happened".
Another - aimed at getting victims "back on their feet" - has pulled in more than £330,000 in donations.
"Tragically, now, we are not expecting to find anyone else alive", she said.
Earlier, Prime Minister Theresa May met with emergency services during a private visit to the site.
-A previous version of this item has corrected the day of Cotton's comments to Thursday, not Wednesday.
Authorities have confirmed 12 deaths, but have said that figure would rise. Dozens of others have been hospitalized.
Grenfell Tower is located in Kensington and Chelsea, statistically the richest neighbourhood in the country, but with the most pronounced wealth disparities. Celebrity chef Jamie Oliver has offered free food for survivors at one of his nearby eateries.
Rising among the stylish town houses that define west London prosperity, the charred remains of Grenfell Tower on the edges of Notting Hill now serve as an ominous reminder of the British capital's vast disparities. The cause of the blaze is under investigation, but a tenants' group had complained for years about the risk of a fire.
"We owe that to the families, to the people who have lost loved ones, friends, and the homes in which they lived". Thirty were still hospitalized on Thursday, with 15 in critical condition.
Although officials would not speculate, experts said Thursday that their focus was still on the building's exterior cladding, which was supposed to be fireproof but which witnesses said had burned like paper, quickly transmitting the fire from unit to unit and from floor to floor. Others said they had warned repeatedly about fire safety in the block.
"There were a lot of people trying to help from the local area, they all knew somebody in there".
In addition to those killed, ambulance crews took 74 people to hospitals after the fire.
The Environment, Transport and Regional Affairs Committee launched an inquiry after a blaze tore through a 14-storey block of flats in Irvine, Ayrshire, in June 1999, killing an elderly man.