A teenage girl trapped in the West London tower block reportedly rang her best friend telling her, “We’re not going to make it, I love you”.
It is now believed the teenager, her two sisters and parents, were all killed in the out of control blaze that has so far claimed 12 lives.
"She's about 13 I think. Nobody has been able to contact any of them since. It's just awful,” local resident Hulya told The Sun.
“There are three daughters - one is about two I think, the other is at primary school and the other at secondary school.”
There are also grave fears held for mother-of-two Ranya Ibrahim, who has not been since sending a harrowing Snapchat message to her friend, saying “forgive me everyone, goodbye”.
“I received a Snapchat video from Ranya at 3am just after the fire started and I haven't heard from her since,” her friend Maseen said at the height of the fire.
“She lives on the top floor and her husband was not home because he is on holiday.”
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Some residents screamed for help from behind upper-floor windows, others tried to throw children to safety, as flames raced through the housing block.
"We could see a lot of children and parents screaming 'Help! Help! Help!' and putting their hands on the window and asking to help them," Amina Sharif, a witness, told Reuters.
"We could do nothing and we could see the stuff on the side was falling off, collapsing. We were just standing screaming and they were screaming."
So far 12 people have been confirmed dead following a fire which ripped through the 24-storey housing block.
Police said they expected the death toll to rise, with up to 600 people thought to have been inside Grenfell Towers 120 flats.
Early on Wednesday morning more than 200 firefighters, backed up by 40 fire engines, fought for hours to try to bring the Grenfell Tower block blaze - one of the most treacherous seen in London for a generation - under control.
London mayor Sadiq Khan said the fire raised questions about the safety of high-rise blocks like Grenfell Tower while the scale of the disaster could delay the announcement of a deal by Prime Minister Theresa May to stay in power.
The ambulances service said 69 people had been taken to hospital and 18 were in critical care.
The cause of the inferno, which left the tower block a charred, smoking shell, was not immediately known. Some residents said no alarm had sounded.