A total of 58 people are missing and presumed dead in the Grenfell Tower disaster, the officer in charge of the investigation said.
Metropolitan Police Commander Stuart Cundy warned that the death toll could rise further as he formally identified a first victim as 23-year-old Mohammed Alhajali.
Earlier on Saturday Prime Minister Theresa May met victims of the blaze at Downing Street, amid criticism she had not seen them in the immediate wake of the tragedy.
Mr Cundy said: "Sadly, at this time there are 58 people who we have been told were in the Grenfell Tower on the night that are missing, and therefore sadly, I have to assume that they are dead."
"That number 58 may change. I really hope it won't, but it may increase.
"Our focus has been on those that we know were in Grenfell Tower. However, there may be other people who were in there on the night that others were not aware were there.
"That is also an absolute priority for the investigation - to establish who they may be," he added.
Mr Cundy also appealed to anyone who may have escaped from the building, but has not yet come forward, to make themselves known.
Of the 58, he said 30 were confirmed dead. 16 bodies have been recovered from the Tower and taken to a mortuary.
Mr Cundy said the police investigation into the blaze would look at the building and its refurbishment in 2016 and vowed to prosecute people "if there is evidence".
He said: "The investigation is a police investigation. We investigate criminal matters. The investigation will identify any criminal offence that has been committed. It will be wide ranging.
"It will go to establish the answers of what happened in the fire and how it spread, it will look at the building itself, it will look at the refurbishment as well.
"Our criminal investigation will identify any criminal offences that have been committed. Wherever we can, we will bring people to justice if there is evidence. It is completely and wholly inappropriate for me to talk about details of the investigation which may subsequently jeopardise any criminal proceedings."
Search and rescue teams from London Fire Brigade reached the second from top floor inside the Tower on Saturday.
On Friday, grief over the disaster turned into anger as protesters took to the streets to vent over the fire which killed at least 30, with dozens more deaths feared.
Mrs May was greeted with cries of "coward" and "shame on you" as she returned to the site of the devastating fire in west London on Friday.
Later, demonstrators stormed the offices of Kensington and Chelsea Council over its handling of the crisis amid concerns that earlier renovation work was linked to the dramatic spread of the blaze.
Hundreds of protesters also marched on Whitehall, central London, to voice their frustration at the Government's response to the fire, which ripped through the tower block in north Kensington on Wednesday morning.
Firefighters who rushed towards danger have spoken of their ordeal - and their fears that the tower could have collapsed like the World Trade Centre.
Leon Whitley (34) described the scene as "hellish", adding: "It was crazy. The screams were coming from all directions. I don't think I will ever forget them".
There was a large police presence as Mrs May met a group of victims, residents, volunteers and community leaders at St Clement's Church close to the scene of the horrific blaze on Friday afternoon.