One person is missing after a crane fell on to houses in east London leaving four people injured.
London Fire Brigade (LFB) said a 20-metre crane collapsed onto a block of flats under development and into two terraced houses on Compton Close, Bow, on Wednesday afternoon.
A video posted on Twitter showed a terraced house with part of the roof caved in.
London Ambulance Service (LAS) said crews have treated four people at the scene, while a spokesman for the LFB said rescue teams are still searching for one person believed to be an adult.
A spokeswoman for LAS said: "We treated two of these patients for head injuries and took them to hospital and we assessed the other two patients at the scene.
More information to follow. pic.twitter.com/qEKxllwuPC
- London Ambulance Service (@Ldn_Ambulance) July 8, 2020
"We are working closely with other members of the emergency services at the scene with more updates to follow."
LFB assistant commissioner Graham Ellis said: "Our urban search and rescue crews are undertaking a complex rescue operation and using specialist equipment to search the properties.
"This is a multi-agency response and is likely to be a protracted incident.
"I would ask people to avoid the area."
The Metropolitan Police said officers were called at around 2.39pm on Wednesday to Gale Street to a report of a crane that collapsed into a residential property and a building site.
Neil Marney, chief executive of Marney Construction, said it was not one of his company's cranes that had collapsed nor was it a crane on one of his sites.
But he said he could see the crane being erected on Tuesday from the site he was working on, telling the PA news agency: "My project manager on the site called me immediately and said the crane you were looking at yesterday being erected has just collapsed.
"So all I could see yesterday was the mast and the cab was on, and then I believe they started to add sections of the boom."