A 12-story, 136-unit apartment complex near Miami beach in the US partially collapsed early Thursday morning, killing at least four, injuring 11 others, and leaving more than 150 people unaccounted for.

Iran PressAmerica: The collapse of the building was first reported to the authority at 1:23 a.m., when most of the residents were asleep, raising fears that the number of casualties could increase further.

After the building’s collapse, the rescue authorities deployed 80 search and rescue teams from the Miami region, and continued rescue operation throughout the night, but it was very difficult to find survivors from layers and piles of debris from the building, according to the Miami Herald and other outlets.

Thirty-five people were pulled from the collapsed part of the building, and two people had been pulled out of the rubble as of Thursday afternoon.

There were 120 people accounted for from the building and 159 people unaccounted for, Miami-Dade County Mayor Daniella Levine Cava told reporters Friday morning.

An eyewitness said that the building collapsed as if a soft cake crumbles, and another resident said, “I thought the building was bombed.”

The ill-fated building “Champlain Tower,” which was constructed in 1981, saw 55 of the 136 units collapse. The exact cause of the accident has yet to be revealed.

Some experts say that since the building is 40 years old, it might have collapsed due to aging of the structure, other experts raise the possibility that it could have collapsed due to land subsidence resulting from global warming.