Rescuers have found at least six bodies in the rubble of three buildings which suddenly collapsed in Rio de Janeiro, Brazil.
Sixteen other people are still missing.
Authorities are still investigating the cause of the tragedy, but officials speculated that illegal construction work damaged the structure of a 20-storey building and caused it to crumble, pulling down two other offices beside it.
A caretaker was among six injured people who were extracted by rescue crews from the heap of bricks, metal and glass.
The missing include an accountant and a computer technician, with friends and relatives waiting in a nearby building, hoping for news. Francisco Adir was trying to get information about a friend, Flavio Porrozi, 23, who had been attending a computer course in the largest of the three buildings.
"We think he's alive. At 3am he managed to call his girlfriend and say 'Hello, love,' before his phone went dead," Mr Adir said. "The rescuers haven't given us any information, but the family is hanging all their hopes on that phone call."
Five of the six bodies pulled out have been identified in the city morgue, and Mr Porrozi is not among them.
According to the institution responsible for approving construction in Rio, unauthorised construction projects were under way in the building.
The head of the accident prevention unit of Rio's Regional Council of Engineering, Luiz Cosenza, told the Globo television network that illegal projects could have led to the collapse. "Two projects were happening in the building," he said. "They were illegal works, they were not registered with the council."
Shortly after the collapse, there was a strong smell of natural gas in the area, but Mayor Paes said it apparently did not cause the problem.