Rescue crews picked through tons of rubble on Thursday looking for survivors after the collapse of part of an oceanfront apartment tower overnight near Miami, where officials reported at least one person dead and nearly 100 missing.

Search teams detected sounds of banging and other noises but no voices coming from the mounds of debris hours after a large section of the Champlain Towers South condominium in Surfside, a barrier island town across Biscayne Bay from the city, crumbled to the ground, authorities said.

What caused the 40-year-old high-rise to tumble into a heap in a matter of seconds was not immediately known, though local officials said the 12-story tower was undergoing roof construction and other repairs.