A seven-storey residential building has collapsed in the city of Fortaleza in north-eastern Brazil.
Firefighters say one person was killed when the apartment block collapsed.
Seven people, among them a 60-year-old woman and a 20-year-old man, have been rescued but 10 more are feared trapped.
Firefighter Cleyton Becerra said the situation remained dangerous as there was a risk that rescuers could get caught in further collapses.
Rescue workers had earlier said that eight people had been rescued but they later revised the figure down. They also said that after speaking to residents they believed the number of people still missing was 10.
One person is reportedly trapped in an elevator.
Video footage posted by neighbours shows a pile of rubble where the seven-storey building once stood and rescue workers searching for survivors.
The apartment block came down at about 10:30 (13:30 GMT).
Local journalist Donizete Arruda posted a video of the scene of the collapse on Twitter.
Firefighters say they received mobile phone calls from some of those buried beneath the rubble and that they were being led to their location with the help of descriptions of where they were when the collapse happened.
Rescue workers have asked for silence at the site while encouraging possible survivors to shout out in order to hone in on them better.
A puppy was also pulled alive from the rubble.
The building in Dionísio Torres, an upscale neighbourhood of Fortaleza, is about 40 years old, a former resident told local news site G1.
Roads around the area have been cordoned off to allow rescue workers better access.
Newspaper Diário do Nordeste tweeted footage of the moments just after the collapse showing dust rising from the rubble.