There are fears people may be trapped after homes were destroyed in a large suspected gas explosion in the Shaw area of Oldham, authorities say.
One person had been taken to hospital with 80% burns, said a spokeswoman for the North West Ambulance Service.
The blast has completely destroyed three homes.
Emergency services are at the scene, which centres on a house near Buckley Street and Duchess Street.
"The control room has received numerous calls from members of the public and the initial information from the public is that it involves a number of terraced properties in Duchess Street with possibly people trapped," the fire service said in a statement.
Police, who were alerted to the blast at 11.15am, said there were no confirmed details on casualties or the number of homes damaged at this stage.