A rescue operation was under way today after the roof of a West Bromwich town centre building collapsed, the fire service said.
Four people known to have been inside the building in High Street at the time have been accounted for but there may have been a fifth person inside.
A West Midlands Fire Service spokesman said: "Four people were in the building at the time of the collapse; two people were rescued by fire service personnel, two left of their own volition.
"The operation is still considered to be in the rescue phase as there is a possibility there is a fifth person in the building."
One of the casualties had a minor head injury while the other sustained a foot injury.
He added: "Technical rescue, structural engineers and sniffer dogs are on the scene, carefully sifting through the building in an attempt to locate any missing persons."
The property is a three-storey building, with a Bairstow Eves estate agent on the ground floor, and residential addresses on two floors above. The fire service spokesman described the incident as a "catastrophic failure" of the roof, adding: "The roof has collapsed inwards, which has caused the floors below to pancake downwards towards the ground floor."
The cause of the collapse is unknown.
West Bromwich High Street was closed to all traffic and was likely to remain so for some time.
West Midlands Police spokeswoman said: "Police were called at 00.44am today to reports of a roof having collapsed at a premises on High Street, West Bromwich.
"People were reported to have been trapped inside a flat above the shop. Four men have been rescued from the building - two of those were taken to hospital, with non-life-threatening injuries.
"High Street remains closed between Carters Green and Shaftesbury Avenue. People are advised to avoid the area if at all possible."