Two men have been left fighting for their lives following an explosion in a flat in Stamford Hill.
The second floor flat caught alight just after 2.30pm today, and witnesses described seeing at least one person jump from the burning building.
Four men, aged in their 20s and 30s, were treated at the scene for burns, before being rushed by ambulance to two separate hospitals.
One of the flats in the block was allegedly being used as a cannabis farm.
Four fire engines and 21 firefighters spent about an hour and a half tackling the blaze at the property in a block of flats in Stamford Hill Estates.
The air ambulance was also scrambled to the scene.
A Metropolitan Police spokeswoman said: "Police were called at 2.38pm to reports of an explosion and fire at a block of flats in Stamford Hill, Hackney, N16.
"Officers attended along with the London Fire Brigade (LFB), the London Ambulance Service (LAS).
"Residents in the flats were evacuated, however there were four casualties, all male, whose ages range between late 20s and early 30s.
"They have been taken to two different hospitals to be treated for the effects of burns. Two of the men are believed to have life threatening or life changing injuries. One of this pair has subsequently been transferred to a specialist unit."
She added that no arrests had been made and detectives from Hackney CID were investigating.
A London Ambulance Service spokesperson said: “We were called at 2.32pm to reports of a fire on Stamford Hill, Hackney.
“We sent a number of ambulance crews, an incident response officer and an advanced paramedic to the scene, alongside our hazardous area response team and London’s Air Ambulance.
“We treated four patients at the scene for burns and took them as a priority to hospital."
