A child has died in an explosion which "completely flattened" a terraced house in the Shaw area of Oldham.
Five houses were damaged in the blast which is thought to have been caused by a gas leak in Buckley Street, Greater Manchester Police (GMP) said.
One man was airlifted from the scene to Wythenshawe Hospital with 80% burns.
Fire and rescue teams were called to search through the rubble for casualties but it is now believed everyone has been accounted for.
Greater Manchester Fire Service said more than 30 firefighters were at the scene in the aftermath, with extra teams being drafted in from neighbouring Lancashire Fire Service.
Specialist search and rescue teams, some of whom have worked in Haiti, New Zealand and Japan, used three dogs to help in the operation.
A fire service helicopter with listening equipment was also called to the scene to try to detect if people were trapped in the rubble.
National Grid said there was a report of a "gas escape" at 10:40 BST.
The company issued a statement saying: "National Grid can confirm that it received a report of a smell of gas in the Edmund Street and Buckley Street area of Shaw at 10.40am today.
"This was shortly followed by another call to report that there had been an explosion.
"Engineers arrived on site to find that five properties - seven to 13 Buckley Street - had been badly damaged."
One hundred homes have been evacuated and Oldham Council has set up a rest centre at Crompton House School in Rochdale Road for residents removed from their homes.
At the scene
Jonathan Ali, BBC Radio Manchester
Fire and rescue teams from across the North West have been searching the devastated area.
They have been using their search and rescue dog Echo to comb through the rubble of these brick terraced houses.
The explosion was so big it was felt as far as half a mile away.
The shockwaves of the blast broke windows, set off car alarms, and littered the tightly packed streets in the area with fragments of roof slates.
The centre of Shaw is at a standstill and the people who live here have been left shocked by the devastation.
Earlier, Supt Neil Evans, of GMP, said: "What I am now able to confirm is that there has been at least one fatality.
"That is believed to be a young child from one of the addresses and the next of kin has been informed."
Alex Perkins, who lives across the road, said: "It's like a war zone - tiles that have blown off literally across the streets, there's just debris everywhere. It's mad.
"It's just empty, there's nothing there, just bricks on the floor, just rubble."
Georgian Ulla, who also lives on the street, said her house "shook like it was an earthquake".
"All the lights shook - I thought someone was breaking in to begin with," she said.
"First thing that I saw was all the toys on the floor. Apparently there are kids that live in the house."
Ashfaq Hussein, whose father is the landlord of the house where the explosion took place, said: "We are absolutely shocked."
He said the man who suffered the serious burns and his partner were due to get married soon.
Shaw ward councillor Mark Alcock, who lives a quarter of a mile away, described the scene as "utter carnage".
"An end-terrace house has been completely flattened and properties up to 800m away have had their windows blown in," he said.
"It's a real mess."
Peter Travis, who works nearby, said: "I heard the loudest bang you could ever hear, then I could see bits of slate going through the air like ticker tape.
"Bits of slate were landing near us about 250 metres away.
"I could then hear alarms going off and then a silence, it was absolutely frightening."
Craig Needham who runs a nearby garage, said staff ran outside when they heard the explosion.
"We could just see a black plume, we thought a bomb had dropped," he said.
Adam Pollard, 21, was due to move in to a property around the corner from Buckley Street and was gathering belongings at his mother's house nearby when he heard the explosion.
"It was the biggest bang I have ever heard, all the windows shook," he said.
"I could see the smoke and came running up towards my flat.
"I got to the street and the three houses that had been there were just rubble, basically.
"I was worried if someone was trapped. I went running on to the rubble, shouting to see if anyone was injured. I couldn't see anyone and there was no fire, just smoke in the air.
"There was a weird smell, not of gas, like a burning smell."
He added: "I can't believe somebody has even been found alive in there.
"The house must have been completely filled with gas."
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