Searching a London tower block that was gutted in a huge fire might take months, a police chief says, adding he hopes the death toll will not rise from 17 to "triple figures".
Commander Stuart Cundy told reporters on Thursday some victims of the blaze which destroyed the 24-storey Grenfell Tower might never be identified.
UK Labour MP David Lammy says the disaster is "corporate manslaughter" and has called for arrests to be made.
"We should call it what it is, it's corporate manslaughter, that's what it is and there should be arrests made, frankly," he told the BBC.
"Many of us across the country have been caught up in an election, knocking on housing estate doors right across the country, travelling up to the top floors of tower blocks and we know as politicians that the conditions in this country are unacceptable.
"They haven't got easy fire escapes, they've got no sprinklers, it's totally, totally unacceptable in Britain that this is allowed to happen and people lose their lives in this way. People should be held to account."
Police have said 17 people were killed in the blaze which began on Wednesday morning, and the death toll is likely to rise.
Asked if the final figure would be double or triple digits, Mr Cundy said: "I'd like to hope that it isn't going to be triple figures."
On Thursday, Theresa May visited the wreckage of the apartment building in west London, and ordered a public inquiry, as public anger grows over how it happened.
The political fallout of the fire, which trapped dozens of people in their beds, is also hurting May's Conservative Party, who run the local council and have been blamed by the opposition for spending cuts that starved budgets for building maintenance and safety checks.
Fire engulfed the social housing block, where as many as 600 people lived in more than 120 apartments, in the early hours of Wednesday, turning it into a flaming torch in minutes.
"Sadly I can confirm that the number of people that have died is now 17," London police commander Stuart Cundy told reporters.
In addition, 74 people were injured in the blaze, with 37 hospitalised and 17 of them still in critical condition.
Fire Commissioner Dany Cotton said it would be a "miracle" if anyone else were to be found alive.
She said urban search units backed by specialist dog teams would slowly make their way through the building as structural surveyors helped make the tower safe.
An investigation into the cause of the blaze is underway but the shock at its scale turned to anger and recriminations on Thursday.
"Right now, people want answers and it's absolutely right and that's why I am today ordering a full public inquiry into this disaster," said Ms May, who visited the scene on Thursday.
"We need to know what happened, we need to have an explanation of this."
Local residents say there had been repeated warnings about the safety of the building, which recently underwent an exterior refurbishment, which included new external cladding and windows.
The government has promised other recently refurbished tower blocks will be assessed.
"We have to get to the bottom of this. The truth has got to come out, and it will," opposition Labour leader Jeremy Corbyn said as he visited volunteers at the site.
Survivors spent the night at emergency shelters, as charities and local support groups were flooded with donations of clothes and bedding from shocked Londoners.
Queen Elizabeth said her thoughts and prayers were with those families who had lost loved ones and with the many people still critically ill in hospital. She also paid tribute to the bravery of firefighters who risked their lives to save others.
Outside the police cordons, impromptu tributes appeared with photos of missing people, messages of condolences, flowers and candles.