Metropolitan Police Commander Stuart Cundy said five people had been formally identified and the rest were "sadly" missing presumed dead.
Some families have lost more than one member, he added. "This is an incredibly distressing time for all of them".
Seventy-nine people are dead or missing and presumed dead following a devastating blaze in a London tower block last week, police said on Monday, as Britain held a minute's silence for the victims.
Mr Cundy said the death toll may still change, but not as significantly as it has in recent days.
On the same morning Cundy delivered his update on the fire, a moment of silence was observed in honor of those it has affected. "On Saturday, I went in myself and went to the top floor".
Speaking later outside Scotland Yard, Mr Cundy added: "I have investigated major crime for most of my service and I have seen some awful things". He expects the operation to last "many, many weeks".
Five people who had been missing following the fire at Grenfell Tower have been found "safe and well".
He said the death toll could still change if anyone reported as missing was found alive, of if anyone was found in the ruined tower who had not been reported as missing.
Fire broke out in the 24-storey Grenfell Tower, a social housing block in Kensington, in western London, in the early hours of Wednesday, trapping residents inside as it tore through the building with terrifying speed.
The fire triggered both sorrow and outrage, as residents described the futility of their earlier attempts to have the building's safety issues addressed, particularly its fire escape plan.
He also criticised Boris Johnson, saying he wants to know why the then London mayor didn't realise that "whatever saving he made by closing these fire stations [in London], wrecking these [firefighting] appliances, sacking these firefighters, might not have to be paid for by something much more valuable than gold, paid for in human blood". The job's contractor has said the work met all fire standards.
Cundy promised an "exhaustive" criminal investigation into the fire that would also look at a major refurbishment of the building completed a year ago.