Hundreds of fire and rescue workers scoured through tons of rubble on Thursday after a 12-storey oceanfront residential building partially collapsed in southern Florida, with at least one person dead and nearly 100 still 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 of Miami, crumbled to the ground, authorities said.
What caused the 40-year-old high-rise to collapse was not immediately known, though local officials said the tower was undergoing "recertification" repairs and that an adjacent building was under construction.
Miami-Dade Police Director Freddy Ramirez told reporters that 99 people were unaccounted for and that 53 others whose whereabouts were initially unknown had since been located, though he did not make clear whether everyone in the second group was alive.
"Fire and rescue are in there with their search team, with their dogs. It's a very dangerous site right now. Very unstable," Ramirez told reporters.
"They're in search-and-rescue mode, and they will be in that mode for a while. They are not quitting. They're going to work through the night. They are not stopping."
Ramirez said the numbers of known casualties and people missing were likely to fluctuate.
"I don't want to set false expectations," he said. "This is a very tragic situation for those families and for the community."
A fire official said 35 people were rescued from the building in Surfside, a seaside enclave of 5700 residents on a barrier island across Biscayne Bay from the city of Miami, including two who were pulled from the rubble as response teams used trained dogs and drones in a search for survivors.
Sally Heyman, a Miami-Dade County Commissioner, told CNN early in the day that officials knew of 51 individuals who "supposedly" live in the building, home to a mix of year-round residents and part-time "snow birds" who spend the winter months in Florida.
Officials said the building, constructed in 1981, was going through a recertification process requiring repairs.
"There were structural issues obviously - the building did collapse," Miami-Dade Mayor Daniella Levine told reporters. She said structural engineers were working with firefighters to shore up the part of the building left standing.
Jenny Urgelles woke up to the news that her parents' building had collapsed. She called them, but both their phones went straight to voicemail, she told WSVN 7 News.
"I am holding on to hope. I'm very desperate to know what's happening," she told the local Fox affiliate.
Footage from WPLG Local 10, a Miami TV station, showed a rescue team pulling a boy from piles of debris, and firefighters using ladder trucks to rescue residents trapped on balconies.
The search effort was slowed by at least one fire that burned at the site as emergency crews doused the rubble with water, local media reported.
Authorities were looking for people who might be in the rubble, as well as trying to identify residents who were not home at 1.30am (local time), when an entire side of the building gave way.
"We all woke up in the early morning hours to a tragic scene," said Florida Governor Ron DeSantis, who toured the scene on Thursday afternoon. "We still have hope to identify additional survivors."
At least six Paraguayan nationals were among those unaccounted for, Paraguay's Foreign Affairs Ministry said, including the sister of Paraguay's first lady, the sister's husband Luis Pettengill and their three children.
Subject to various inspections
The Champlain Towers South had more than 130 units, about 80 of which were occupied. It had been subject to various inspections recently due to the recertification process and the adjacent building construction, Surfside Commissioner Charles Kesl told Local 10.
"There were garage-underground issues related to that, to make sure that it was done soundly," Kesl said.
"There were some cracks from that project - minor cracks - that were just patched up. Nothing, based on my understanding, to the magnitude that would indicate that there was a structural problem that could result in something so catastrophic."
Surfside Mayor Charles Burkett said construction work was being done on the roof of the Champlain Towers South but there was no indication that it caused the collapse.
"It's hard to imagine how this could have happened," Burkett told reporters. "Buildings just don't fall down."
Burkett said the collapse left about a third or more of the building - a section with balconies facing the beach - "totally pancaked."
Resident Barry Cohen and his wife were rescued from the building.
"At first it sounded like a flash of lightning or thunder," said Cohen, a former Surfside vice mayor and building resident. "But then it just kept on - steadily for at least 15 to 30 seconds - it just kept on going and going and going."
Cohen also said there had been construction for more than a month on the building's roof.
The Miami-Dade Police assumed control of the investigation. More than 80 fire and rescue units responded, the Miami-Dade County Fire Rescue Department wrote in a Twitter message early on Thursday.
Miami-Dade Fire Rescue assistant chief Raide Jadallah said that rescuers were moving in "heavy equipment" and working to support the remaining structure of the building.
"We are still continuing the search and rescue operations," Jadallah said.
Burkett said that part of the building with balconies facing the beach "pancaked" where one floor appears to have fallen atop another, cascading down.
"The back of the building, probably a third or more, is totally pancaked," he said.
Eyewitness video obtained by Reuters showed neighbours gathering across the street from the rubble.
"This whole building here, it's completely gone," a person can be heard saying.