More than 200 firefighters are still tackling a massive blaze at a 27-storey block of flats in London, with reports of people were trapped in their homes.
Forty fire engines were called to the 120-apartment Grenfell Tower, on the Lancaster West Estate, north Kensington, in the early hours of Wednesday. The estate is on Latimer Road, White City.
The Metropolitan Police said residents were being evacuated from the tower block.
The London Ambulance Service said it had taken 30 patients to five hospitals while police say a "number of people are being treated for a range of injuries", including smoke inhalation, as pictures showed flames shooting metres into the sky, engulfing most of the block.
The Guardian reports more than 200 people live in the burning tower, which is part of a large housing estate.
CNN reported that a witness said people were jumping from the burning building.
A witness told BBC radio "It's just an inferno. I can hear people screaming, 'Help me, help me,' but the building is too big."
As dawn broke, columns of thick black smoke continued to rise from the building and ash filled the air, as firefighters tackled the blaze form the ground.
Actor and writer Tim Downie, who lives about 600 metres away, said he feared the block could collapse.
"It's horrendous. The whole building is engulfed in flames. It's gone. It's just a matter of time before this building collapses.
"I just hope they have got everyone out. People have been bringing water, clothes, anything they've got to help, out to the cordon," Downie said.
"I have seen people coming out in their bedclothes - it's just very distressing."
The London Fire Brigade said the cause of the fire was not known at this stage. At 6.30am local time it said 30 adjacent flats have been evacuated by police.
"We are dealing with a really serious fire that spread throughout the building," a spokesman for the fire brigade told Reuters. "The crews are doing all that they possibly can to tackle this fire."
A witness told Reuters that she feared not all the residents had escaped. Some were evacuated in their pyjamas.
Fabio Bebber wrote on Twitter: "More screams for help as the fire spreads to another side of the building.
"We can see how quick the fire spreads via the external panels. It's unbearable hearing someone screaming for their lives at #grenfelltower."
George Clarke, who presents the Channel 4 TV show Amazing Spaces, told Radio 5 Live: "I'm 100 metres away and I'm absolutely covered in ash.
"It's so heartbreaking, I've seen someone flashing their torches at the top level and they obviously can't get out.
"The guys are doing an incredible job to try and get people out of that building, but it's truly awful," he said.
He later told the BBC he was "getting covered in ash, that's how bad it is".
"I'm 100 metres away and I'm absolutely covered in ash."
Andy Moore who works for the BBC said the whole tower block was alight and there were fears the building might collapse.
London Mayor Sadiq Khan used Twitter to urge people to follow the fire brigade's account for more information on what he called the "major incident".
Met police said cordons were in place and advised that the estate and surrounding area should be avoided.
Police said it has closed the A40, a major road leading out of west London, to allow emergency services to access the site.
The London Ambulance service said it had dispatched 20 crews to the scene.
"Our initial priority is to assess the level and nature of the injuries an ensure those in most need are treated first and taken to hospital," it said in a statement.
BBC correspondent Simon Lederman told the broadcaster he understood "a significant number of people" were unaccounted for.
There has been a long-running dispute between some residents of the tower block and the management agency. A community organisation called the Grenfell Action Group had expressed worry about fire in the building following an earlier incident in 2013.
In November the group said it was their "conviction...that a serious fire in a tower block or similar high density residential property" would expose the management company's practices.
On Wednesday morning, it published a new blog post declaring in bold letters "All our warnings fell on deaf ears" and publishing links to its previous warnings.
"Regular readers of this blog will know that we have posted numerous warnings in recent years about the very poor fire safety standards at Grenfell Tower and elsewhere in RBKC."
The group said the tower had "narrowly averted a major fire disaster...in 2013 when residents experienced a period of terrifying power surges that were subsequently found to have been caused by faulty wiring."
The Grenfell Tower has recently undergone a €8.6million ($14.5 million) refurbishment with insulated exterior cladding, according to the Kensington and Chelsey council. "The large scale works included the installation of insulated exterior cladding, new double glazed windows and a new communal heating system," the council website says.
It is managed by the Kensington and Chelsea Tenant Management Organisation (RBKC) on behalf of the council.
It is too early to say whether any materials have contributed to the fire. Combustible cladding has contributed to the spread of other major high-rise fires around the world, including in Melbourne, where a polyethylene facade was found to have fuelled a blaze in an apartment building and in Dijon France, where a fire claimed the lives of seven people in 2010.
The company that refurbished the 1970's London block, Rydon, says on its website the upgrade includes "rain screen cladding, curtain wall facade and replacement windows were fitted, improving thermal insulation and modernising the exterior of the building".
"Internally, lower floor space was remodelled to incorporate extra new homes as well as a nursery, which was relocated from another part of the building. A completely new heating system was installed, which contributes to reducing living costs of residents."
Rydon's website says "resident liaison is an important part of this redevelopment and residents were actively consulted as the project progressed". The company advertises a webcam trained on the tower, but the footage does not appear to have been updated since June last year.
The council issued a series of statements on Twitter on Wednesday saying its major emergency plan had been activated and an emergency rest centre was open for evacuees.
With agencies, Aisha Dow