Firefighters have now successfully rescued two men from one of the flats close to the collapse.
Crews remain at the scene.
More top news
A 64-year-old paperboy who deliberately set fire to his employers' house in a bid for revenge after his benefits were cut has been jailed.
Tesco staff and customers feared for their lives as a store was held-up at gunpoint by a pair of masked robbers.
A police chief constable's bid to have his gross misconduct hearing thrown out has been dismissed.