President Joe Biden sought Thursday to comfort families of people killed or missing in the rubble of a Florida beachfront apartment building, where rescuers suspended their increasingly hopeless task due to dangerous conditions.
The desperate search at the Surfside condo building near Miami took a grim new turn when authorities paused work amid fears that the rest of the structure could also collapse.
Miami-Dade Fire Rescue Chief Alan Cominsky warned that there was "a large column hanging from the structure that could fall" and that movements in the ruins "could cause additional failure of the building."
The 18 confirmed dead so far include two children, aged four and 10, Miami-Dade County Mayor Daniella Levine Cava said late Wednesday. More than 140 others remain unaccounted for and hopes of finding any alive are evaporating.
Biden and First Lady Jill Biden left the White House early for Surfside, saying they wanted to support first responders and comfort grieving relatives.
"What you're doing now is just hard as hell," Biden told emergency workers. "I just want to say thank you. Thank you, thank you, thank you."
He was scheduled to spend as much as three hours with families in private.
"The president and the first lady will meet with the families who have been forced to endure this terrible tragedy, offer them comfort during this unimaginable, difficult time," deputy spokeswoman Karine Jean-Pierre said.
With Florida a crucial state on the US election map, there was considerable focus on interactions during the visit between Biden and state Governor Ron DeSantis -- a rising Republican star who has been touted as a possible 2024 presidential candidate.
In another political twist to the aftermath of the catastrophic accident, former president Donald Trump was planning a rally in Sarasota, Florida, on Saturday. DeSantis has joined calls for postponing the event, which is part of Trump's attempt to remain the dominant force in Republican politics.
Biden, who has made attempts at bipartisan unity a central theme of his presidency, made a point of publicly joining with DeSantis, who himself praised the president for having been "supportive" from "day one."
"We're letting the nation know we can cooperate when it's really important," Biden said.
'Low' chance of survival
The cave-in of the 12-story Champlain Towers South building has sparked a search-and-rescue effort involving engineers and specialists from across the United States and as far afield as Mexico and Israel.
Elad Edri, deputy commander of an Israeli search and rescue team, said rescuers had completed a map outlining the bedrooms and other living spaces in the building where residents could have been trapped.
Rescuers made it to an underground parking structure where it had been hoped they might discover people who had been trapped in cars, but found no one, Edri said.
"It's been more than six days from the collapsing," he cautioned, deeming the chances of finding any survivors "low."
Residents in the part of Champlain Towers South that remained intact reported being awakened around 1:30 am (0530 GMT) Thursday by what sounded like cracks of thunder that shook their rooms.
"It was like an earthquake," Janette Aguero, who escaped from the tower's 11th floor with her family, told AFP.
Rescuers who arrived in the moments after the tower came down helped evacuate dozens of residents, and pulled one teenage boy alive from the rubble.
Since then, no other survivors have been found, despite deployment of sniffer dogs and cranes for lifting debris.
Experts are looking at possible pre-existing critical flaws in the structure of the apartment tower.
An October 2018 report released by city officials revealed fears of "major structural damage" in the complex, from the concrete slab under the pool deck to the columns and beams in the parking garage.
In a letter to residents in April, Jean Wodnicki, the chair of the condo association, described "accelerating" damage to the building since then.
Repairs had been set to begin soon in the 40-year-old building.