LONDON (AP) — A deadly overnight fire raced through a 24-story apartment tower in London on Wednesday, killing at least six people and injuring 74 others, police said. Witnesses reported seeing residents throw babies and small children from high windows to people on the sidewalk in a desperate effort to save them from the flames.

The inferno lit up the night sky and spewed black smoke from the windows of the Grenfell Tower in North Kensington, where more than 200 firefighters battled the blaze. A plume of smoke stretched for miles across the sky after dawn, revealing the blackened, flame-licked wreckage of the building, which was still burning over 12 hours later.

People trapped by the quickly advancing flames and thick smoke banged on windows and screamed for help to those watching down below, witnesses and survivors said. One resident said the fire alarm did not go off.

“The flames, I have never seen anything like it, it just reminded me of 9/11,” said Muna Ali, 45. “The fire started on the upper floors … oh my goodness, it spread so quickly. It had completely spread within half an hour.”

“This is an unprecedented incident,” Fire Commissioner Dany Cotton told reporters. “In my 29 years of being a firefighter I have never, ever seen anything of this scale.”

She said she feared more victims would be found still inside the building.

There was no immediate word on the cause of the blaze, but angry residents said they had warned local authorities about fire issues at Grenfell Tower. The subsidized housing block of 120 apartments was built in 1974 and was recently upgraded at a cost of 8.6 million pounds ($11 million), with work finishing in May 2016, according to the Royal Borough of Kensington and Chelsea.

Samira Lamrani, a witness, said one woman dropped a baby from a window on the ninth or 10th floor to people on the sidewalk.

“People were starting to appear at the windows, frantically banging and screaming” and one woman indicated she was going to drop the baby, Lamrani told Britain’s Press Association news agency. “A gentleman ran forward and managed to grab the baby.”

Police commander Stuart Cundy gave the death toll of six but added the figure was likely to rise “during what will be a complex recovery operation over a number of days.”