Commander Stuart Cundy said the number "may increase" and the recovery operation is likely to take weeks.
"I believe there may be people who were in Grenfell Tower that people may not know were missing and may not have realized they were in there on the night".
Meanwhile, London mayor Sadiq Khan has said that high-rise tower blocks dating from the 1960s and 1970s could be torn down in the wake of the deadly fire. "We need to find out precisely what cladding was used and how it was attached".
In this photo released by the Metropolitan Police on Sunday, June 18, 2017, a firefighter stands outside of the Grenfell Tower after fire engulfed the 24-storey building, in London. Some 600 people were living in the tower's 120 apartments.
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But now, The Independent has confirmed that the family have not suffered from any casualties, one the daughters confirmed on Facebook that they were not injured but have lost everything.
"The response of the emergency services, National Health Service, and the community has been heroic", Ms May said in a statement.
She told BBC One's Sunday Politics: "We are still hearing stories of people not being allocated properly".
"The last I heard was the children were staying with school pals while the parents were waiting to be rehoused".
He continued: "There's a feeling that the council and successive governments don't understand their concerns and, frankly, don't care".
Five days after the fire that sparked criticism for the government and other authorities, police are still trying to confirm the total loss of life - as well as the cause. What emerges in the coming weeks and months will be very hard for many people, including politicians and organisations, but we must get to the truth, Mr Khan continued. "The country has witnessed a succession of awful tragedies".