US rescuers have made the “extremely difficult decision” to end their search for survivors in the rubble of an apartment building which partially collapsed nearly two weeks ago in the state of Florida, Miami-Dade county mayor Daniella Levine Cava said on July 7.

“It is with deep profound sadness … that we made the extremely difficult decision to transition from operation search and rescue to recovery,” Levine Cava told reporters in Surfside, near Miami, adding that the transition would formally take place at midnight.

“At this point, we have truly exhausted every option available to us in the search and rescue mission.”

Levine Cava said eight more bodies had been found in the debris of the 12-storey Champlain Towers South, which pancaked on June 24 as dozens of residents slept inside, sending up a huge cloud of dust and rattling US citizens unprepared for such a deadly urban disaster.

That brought the official death toll to 54, with 86 people still unaccounted for. Levine Cava said investigators would continue to work to verify whether each of them had been in the building when it collapsed.

No survivors have been found since the day of the collapse. Dozens of rescuers, engineers and specialists, including teams from Israel and Mexico, aided in the search along with sniffer dogs and heavy equipment.

On July 6 officials said 124 tonnes of debris had been removed so far.

Earlier on July 7, Levine Cava said emergency personnel had been able to reach new areas in the pile of debris as a result of the demolition of the remainder of Champlain Towers South in a controlled explosion over the weekend.

Investigations are under way to determine the cause of the collapse.

Survivors reported being awakened around 1:30am (0530 GMT) on June 24 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.

A 2018 report released by city officials revealed fears of “major structural damage” in the complex, from the concrete slab under the pool deck to columns and beams in the parking garage.

In a letter to residents in April, Jean Wodnicki, chair of the condo association, described “accelerating” damage to the 40-year-old building since then, and repairs had been set to begin soon.

Local authorities have also ordered reviews of other nearby buildings.

Levine Cava said rescuers were lucky as the weather had cleared, with Tropical Storm Elsa making landfall on the Sunshine State’s west coast.

US President Joe Biden visited the grieving relatives in Surfside on July 1, and praised their resilience.