More than 200 people have died after a huge fire raged through the night at a west London tower block, a fire chief says.
Eyewitnesses said they saw people trapped inside the burning Grenfell Tower, in north Kensington, screaming for help and assistance, and shouting for their children to be saved.
More than 50 people are being treated in hospital, says London Ambulance.
"We can confirm that we have taken 30 patients to five London hospitals following the incident," Stuart Crichton, assistant director of operations at the London Ambulance Service said, adding that more than 20 ambulance crews as well as a "hazardous area response team" were at the scene.
Two hundred firefighters and 40 fire engines are battling to defuse the fire.
The whole 27-storey block had been alight and there were fears the building might collapse.
BBC correspondent Simon Lederman said he understood "a significant number of people" were unaccounted for.
At 6.15 BST, London Ambulance Service said 20 ambulance crews had been at the scene, 30 people had been taken to hospital, but the nature and level of their injuries was not yet clear.
Mayor of London Sadiq Khan said a "major incident" had been declared.
At about 04:00 BST police said: "Residents continue to be evacuated from the tower block."
Eyewitnesses said they have seen lights - thought to be mobile phones or torches - flashing at the top of the block of flats.
Others say residents - thought to be trapped inside - were seen coming to their windows.
An unmanned hydraulic platform has been shooting water at the side of the building at about the 10th floor.
Simon Lederman said firefighters had not been able to tackle the flames on higher storeys.
He said the tower could be seen burning "from miles away", adding that the building had been "burning out of control", from the tenth floor onwards.
Andy Moore added: "We've seen debris falling from the building, we've heard explosions, we've heard the sound of glass breaking.
"The police keep pushing back their cordons, pushing back members of the public for fear the building might collapse."
The fire brigade said the fire was from the 26th floor.
The Metropolitan Police said "an evacuation process is under way".