London police say the death toll in the apartment building blaze has risen to 17.
The huge fire enveloped the Grenfell Tower block in west London in the middle of the night on Wednesday and the toll is predicted to rise further.
As well, 37 people are receiving treatment, and 17 of those are still in critical care.
Police announced tonight that search crews will use dogs in the building first, because they are lighter and can get into areas people can't.
The core of the building is structurally sound, allowing fire crews to search from the stairwell. However it could take weeks to check all rooms in lower floors, and to safely search the upper half of the building.
London Met Police are now asking people to report anyone who was missing and has now been found.
The Fire Service won't confirm reports the fire started with a fridge or freezer in a fourth floor apartment.
However London's fire chief admitted he is worried about the mental and physical health of many of the firefighters who worked on the Grenfell Tower inferno.
Commissioner Dany Cotton told media in London the 250 officers "saw and heard things on a scale they'd never seen before" as they worked through the night to rescue people from as high as the 24th floor.
"I spoke to some of them yesterday who were truly distressed, not least of all because they knew there were people still in there.
"They were battling through the heat and couldn't get there."
"What went on yesterday truly traumatised a lot of people. It will affect a lot of people.
Officially, 17 people have died in the huge fire that enveloped the Grenfell building in the middle of the night in London yesterday, but Cotton said authorities "have absolutely no idea" how many people were unaccounted for.
She praised the bravery of firefighters who ran into the flames, reaching the 24th floor of the building to rescue people from inside but said it would be an "absolute miracle" if there were any further survivors.
"They were in fear of their own lives. They were in and out of that building committing time after time to rescue the people that were in there.
"They were never going to stop until they physically couldn't get in there any more."
"They are heroes but they have feelings and people were absolutely devastated by yesterdays events."
The brigade has also warned the edges of the building are not safe and it's understood officers will conduct a "fingertip" search of the block, which is expected to take weeks.
UK Prime Minister Theresa May visited the scene today, and other local councils around London have committed to a review of building fire safety.
Cotton said it will be a miracle if any survivors are found following the devastating high-rise fire. Authorities have said many more victims are expected.
Cotton told Sky News that authorities don't expect to find anyone else alive after the blaze and that it's too early to speculate on how it started - or even how many people died. She said that authorities have finally extinguished the last pockets of flame, and are trying to secure edges of the building for a fingertip search.
Meanwhile, construction plans show the perilous maze residents had to navigate to make their way to the building's single fire escape.
Renovations of the Grenfell building in North Kensington saw the building not only kitted out in controversial cladding that could have caused the deadly blaze to spread so quickly, but also stripped of two of its fire exits.
Planning documents submitted to the council between 2012 and 2014 show a collection of compact living spaces packed in tightly together on each floor. According to floor plans 120 apartments were jammed into the building's 24 storeys, all around a central elevator and fire escape.
Leading London fire and building inspector Geoff Wilkinson said that having only one fire escape may have made the escape more difficult for some residents, but it still should have been adequate.
"We can tell that reports [concerning fire safety] were made and the fire service had made inspections relatively recently," he told ABC radio.
"The question of having a single fire exit is not uncommon. It's certainly proved to be [adequate] in the past."
A major refurbishment of the Grenfell Tower, originally built in 1974, was completed in May 2016 at a cost of $14.6 million.
Questions are being raised about what caused the apartment block to turn into a blazing deathtrap, as witnesses reveal residents were advised to "stay put".
One resident who said he and his neighbours had complained about the building's safety for years said he considered the disaster "mass murder" as experts focused on the building's external cladding, fitted only a year ago, that could have turned the tower into a death trap.
Local media is reporting "nobody on the top three floors survived", crediting the claim to a local community leader.
Other witnesses reported not hearing smoke alarms in the building until they were manually started by fire services. Lack of access to the building because of narrow roads and gas works in the area were also cited by locals as complicating firefighting efforts.
London Mayor Sadiq Khan said firefighters were only able to reach the 12th floor and pledged to get to the bottom of whether the response was adequate and residents were at risk.
"The reason it should be such a big concern for all of us is that there are many tower blocks across London and across the country," he said.
"Many of them are the responsibility of local authorities. We need to make sure that legitimate questions people have are answered."
A man has been arrested over allegations he posted pictures of a Grenfell Tower victim on social media.
Images were posted of what appear to be a partially covered body.
The Metropolitan Police said a 43-year-old man was arrested on suspicion of sending malicious communications and obstructing a coroner.
Officers confirmed the arrest related to the fire at Grenfell Tower and the man was in custody.