A boy asked "how many children have died?"
A strong campaigner on mental health, the Duke said it was important that those affected talked about the trauma they had witnessed and urged volunteers to get the right support.
The Theresa May government on Friday was grappling with the aftermath of Wednesday's blaze at Grenfell Tower, amid rising anger among residents and demands by the Labour Party to acquire over 1,000 empty houses for those rendered homeless.
Many people from the 120 flats remain missing, with relatives and friends desperately appealing for information.
The death toll stands at 17, but that could greatly increase, as rescue officials said they're not expecting to find any more survivors.
Syrian refugee Mohammed Alhajali, 23, was also killed in the fire.
"Mohammed undertook a risky journey to flee war and death in Syria, only to meet it here in the United Kingdom, in his own home".
So far, 17 people have been reported dead in the fire and some 70 people have been hospitalized for injuries sustained in the incident, including 20 people whose condition is critical. The process will be very long.
"A priority of each and every one of us involved in the ongoing operation at Grenfell Tower is to recover and identify all the victims", he said.
A woman touches a missing poster for 12-year-old Jessica Urbano on a tribute wall after laying flowers on the side of Latymer Community Church next to the fire-gutted Grenfell Tower in London, Friday, June 16, 2017, after a fire.
Firefighter Lucy Masoud questioned why the blaze spread so rapidly "Something has gone seriously wrong".
The focus of criticism centres on the cladding fitted to external walls on the 1970s concrete block as part of a £8.7 million (RM47.6 million) refit completed previous year. The renovation included the cladding of the entire exterior of the building, which residents have reportedly blamed for the speed at which the fire spread.More news: Emmanuel Macron Set for 'Unhealthy Monopoly' in French Elections
Construction firm Rydon, which carried out the refurbishment, initially said in a statement that the work met "all fire regulations" - the wording was omitted in a later statement.
A lawyer for the family told CNN that Trevisan was able to speak with her parents before she died, telling them: "I am going to heaven".
"From the moment they would have heard about the fire, waking up that morning seeing the bad scenes on their television sets I think they would have been immediately anxious about their families".
British Prime Minister Theresa May has promised a full investigation into the fire, one of the deadliest in United Kingdom history.
Official fire service advice for residents to stay in their homes and use towels to block out smoke, while awaiting help, has also come under scrutiny. "People deserve answers, the inquiry will give them".
"We pray for all the residents of the Grenfell Tower".
"If this happened somewhere near Knightsbridge this would have been resolved".
More than £480,000 had been raised online for the victims by early Thursday, while local community centres were inundated by donations of clothes and food.
Teams were forced to leave the building on Thursday afternoon when the fire restarted, delaying further the efforts to reach upper floors, where some victims are thought to have been trapped.
"If the same concerns were had in a wealthy part of Kensington and Chelsea they would have got resolved, but here they didn't get resolved", Collins told AFP.
An emergency government funding scheme was launched to help meet the costs of the disaster.