A huge fire has raged through the night at a west London tower block, with eyewitnesses claiming people were trapped inside.
More than 200 firefighters are still tackling the blaze at Grenfell Tower in north Kensington, where hundreds of people are thought to live.
London Ambulance said 30 people are receiving hospital treatment.
The BBC’s Andy Moore said the whole 24-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.”
London Fire Brigade assistant commissioner Dan Daly said firefighters were “working extremely hard in very difficult conditions to tackle this fire”.
“This is a large and very serious incident and we have deployed numerous resources and specialist appliances.”
London Ambulance Service medics specially trained in life-saving medical care in hazardous environments have also been sent to the fire.
The first reports of fire in the tower, in Latimer Road, on the Lancaster West Estate, came in at 00:54 BST.
The A40 Westway was closed in both directions. London Underground said the Hammersmith and City and Circle lines have been closed between Edgware Road and Hammersmith.
