Around 120 firefighters are battling a huge blaze raging on the roof of a block of flats in London.
More than a dozen people fled the building in Creek Road, Deptford, before fire crews arrived.
An eyewitness said the blaze is believed to be 'due to building works', although London Fire Brigade (LFB) said the cause is currently unknown.
One terrified resident said he 'legged it' out of the building after going upstairs to investigate the source of smoke in his flat and spotting the fire.
The 26-year-old, who lives on the top floor of the block, told The Mirror: "We were in our bedrooms and we saw smoke and could smell smoke coming in.
"We left it for about 10 minutes until we decided we needed to look upstairs see what they're doing... there's contract work going on.
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"We went upstairs and saw the fire and were like right we need to get out. We grabbed a couple of things and legged it out of the building.
"The fire has spread slowly across the roof and between the gaps in the building."
The resident said all of his neighbours have escaped the block.
Catherine Woodhouse, who lives opposite the block, tweeted: "Raging fire in a block of flats on Creek Road in Greenwich.
"Believed due to building works. I watched it ignite in what seemed like 1-2 minutes. It has been going since 1pm. Fire brigade arrived SO quickly 3 min or so after we called."
She later added: "2 hours later fire still going, firemen inside the flats as well as on cherry pickers.
"Worst fire I’ve ever seen so brave to literally head inside a burning building. #londonfirebrigade @LondonFire you guys are heroes!"
Ms Woodhouse told The Mirror: "The flat on fire has wooden decking and wooden bamboo panelling with electrical cables that caught fire.
"I saw it ignite and a builder down below shouted 'yeah there will be smoke we are doing building works'.
"I was shouting to the people in the flats to escape, he (the builder) initially was telling me to stop. When he realised - as the smoke got bigger - he scrambled up the scaffolding to remove what looked like a gas canister off the roof."
LFB Station Commander Ian Smith, who is at the scene, said: "This is an intense fire located in the roof of the building and fire crews are working hard in challenging conditions.
"We've increased the number of fire engines because of the need for more firefighters in breathing apparatus.
"There is a lot of smoke from the incident and we'd ask local residents to close their doors and windows."
A LFB spokesman added: "Twenty fire engines and around 120 firefighters are dealing with a fire on the roof of a block of flats on Creek Road in Deptford.
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"Around 13 people left the building before the Brigade arrived. There have been no reports of any injuries.
"The LFB was called at 1.03pm The cause of the fire is not known at this stage. Fire crews from Deptford and surrounding fire stations are at the scene."
Greenwich West Police added: "Large fire on Creek Road as you head towards Deptford. Please avoid where possible. Road is currently closed."