Sally Heyman, a Miami-Dade County Commissioner, said officials are unable to form contact with 51 people that "supposedly" sleep in the building, home to a mixture of individuals including families and part-time "snow birds" who spend the winter months in Florida.
"We have 51 folks that were assumed to possess been there, but you do not know between vacations or anything , so we're still waiting," Heyman told CNN by phone. "The hope remains there, but it's waning."
A fire official said 35 people were rescued from the building in Surfside, a seaside enclave of 5,700 residents on a island across Biscayne Bay from the town of Miami, including two who were pulled from the rubble as response teams used trained dogs and drones during a look for survivors.
After speaking with local officials, Florida Governor Ron DeSantis said it had been possible that more victims might be found within the rubble. He said he planned to travel to scene.
"We'll hope for the simplest in terms of additional recoveries, but we are bracing for a few bad news, just given the destruction that we’re seeing," DeSantis said at an occasion at a junior college near Tampa.
Built in 1981, the Champlain Towers South had quite 130 units, about 80 of which were occupied.
It was unclear what percentage people were inside at 1:30 a.m. (0530 GMT), when a whole side of the building pulled away and fell to the bottom below.
"It's hard to imagine how this might have happened," Surfside Mayor Charles Burkett told reporters. "Buildings just don't subside ."
Construction work was being done on the roof, he said, but it had been unclear whether the project involved any heavy gear.
Footage from WPLG Local 10, a Miami television station , showed a rescue team pulling a boy from piles of debris and rebar, and firefighters using ladder trucks to rescue residents trapped on balconies.
Assistant fire marshal of Miami-Dade Fire Rescue Raide Jadallah said that rescuers were occupation "heavy equipment" and dealing to support the remaining structure of the building.
"We are still continuing the search and rescue operations," Jadallah said.
Burkett said that a part of the building with balconies facing the beach "pancaked" where one floor appears to possess fallen atop another, cascading down.
"The back of the building, probably a 3rd or more, is completely pancaked," he said.
Resident Barry Cohen and his wife were rescued from the building.
"At first it seemed like a flash of lightning or thunder," Cohen, a former vice mayor of Surfside and a resident of the building, told reporters at the scene. "But then it just kept on -- steadily for a minimum of 15 to 30 seconds -- it just kept on going and going and going."
Cohen also said there had been construction for quite a month on the building's roof.
The Miami-Dade Police have assumed control of the investigation. quite 80 fire and rescue units responded, the Miami-Dade County Fire Rescue Department wrote during a Twitter message early Thursday.
Eyewitness video obtained by Reuters showed neighbors gathering across the road from the rubble.
"This whole building here, it's completely gone," an individual are often heard saying.
