The fire broke out in a high-rise building in the east of the English capital, with dozens of firefighters tackling the blaze, according to the London Fire Brigade.
"Fifteen fire engines and 100 firefighters are dealing with a very visible fire on Whitechapel High Street. Please avoid the area if possible. Follow this account for the latest information,” London Fire Brigade spokesman said.
Large glass panels are falling hundreds of metres to the ground, according to the witnesses.
"There are significant road closures in place and we are asking people to avoid the area and keep windows and doors closed whilst firefighters work to bring the fire under control," Station Commander James Ryan said as quoted by the Sky News.
According to him, nearby buildings have been evacuated.
The cause of the blaze is not yet unknown.