A suspected arson attack forced 30th birthday party revellers to jump from the window of a Salford flat.
About 15 people were in the property at Fernside Grove, Walkden, when the fire started at 05:30 BST.
Police said wheelie bins were pushed in front of the door of the building and set alight. It is not yet clear why the site was targeted.
Two women jumped from a first-floor window and suffered leg injuries, the fire service said.
Greater Manchester Police said an investigation was underway and appealed for witnesses.
The proximity of combustibles should have been picked up on the fire risk assessment for this block of flats and alternative methods developed to ensure that this level of risk was removed or reduced.