A child has died in an explosion which "completely flattened" a terraced house in the Shaw area of Oldham.
The house in Buckley Street was destroyed and many other houses were damaged in the blast, which is thought to have been caused by a gas leak.
One man was pulled from the rubble and airlifted to Wythenshawe Hospital with serious burns.
Fire and rescue teams have been searching for casualties but it is now believed everyone is accounted for.
Greater Manchester Fire and Rescue Service said it would remain at the scene until it and police confirmed they were not looking for anyone else.
Station manager Dean Nankivell said: "The scene down there is catastrophic. It's just a great big pile of bricks.
"Whatever has caused this has gone with some force. Gas is definitely a strong contender.
"If there is anybody in there, we will be there until we find them."
The fire service said more than 30 firefighters were at the scene in the aftermath, with extra teams drafted in from neighbouring Lancashire Fire Service.
The Urban Search and Rescue Team, some of whom have worked in Haiti, New Zealand and Japan, used three sniffer dogs to help in the operation.
A fire service helicopter 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 were evacuated and Oldham Council set up a rest centre at Crompton House School in Rochdale Road for residents removed from their homes.
Councillor Jean Stretton, who is helping to co-ordinate facilities for residents, said there was a "blitz spirit" at the centre.
"There is a mix of people who are quite subdued because of the shock of what has happened here today, but there is also a lot of community spirit going on," she said.
"We've had a lot of support from the local community with people coming and bringing donations of clothes and baby chairs. The local stores have brought things like food and nappies and water, there has been a fantastic response."
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."
Police had said another person was trapped in the debris, but later confirmed that person had been accounted for.
The man who was taken to hospital was initially believed to have been suffering 80% burns, but the North West Ambulance Service later said he was suffering about 25-30% burns.
Mr Nankivell, who is also head of the fire service's Urban Search and Rescue Team, said structures damaged in the blast had to be stabilised to make the area safe enough for investigators to go in.
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."