SURFSIDE, Fla. (AP) — About 160 people were still unaccounted for Friday after an oceanside condominium building collapsed into a smoldering pile of rubble, and searchers using both heavy machinery and their own hands to comb through the shifting heap of concrete and metal feared the death toll of four could soar.

With scores of firefighters working overnight in Surfside to reach any possible survivors from under and atop the remains of the 12-story Champlain Towers South, hopes rested on how quickly crews using dogs and microphones could complete their grim, yet delicate task.

“Any time that we hear a sound, we concentrate in that area,” Miami-Dade Assistant Fire Chief Raide Jadallah said. “It could be just steel twisting, it could be debris raining down, but not specifically sounds of tapping or sounds of a human voice.”

Buffeted by gusty winds and pelted by intermittent rain showers, two heavy cranes began removing debris from the pile using large claws Friday morning, creating a din of crashing glass and metal as they picked up material and dumped it to the side.

Once the machines paused, firefighters wearing protective masks and carrying red buckets climbed atop the pile to remove smaller pieces by hand in hope of finding spots where people might be trapped. In a parking garage, rescuers in knee-deep water used power tools to cut into the building, according to video released by Miami-Dade Fire Rescue.

Surfside Mayor Charles Burkett said crews were doing everything possible to save as many people as they could.

“We do not have a resource problem, we have a luck problem,” he said.

Nearby, visitor Faydah Bushnaq of Sterling, Virginia, knelt on the beach and scratched “Pray for their souls” in the sand.

“We were supposed to be on vacation, but I have no motivation to have fun,” Bushnaq said. “It is the perfect time to say a prayer for them.”

Three more bodies were removed overnight, and Miami-Dade Police Director Freddy Ramirez said authorities were working with the medical examiner’s office to identify the victims. Eleven injuries were reported, with four people treated at hospitals.

Miami-Dade Mayor Daniella Levine Cava said rescuers were at “extreme risk” going through the rubble.

“Debris is falling on them as they do their work. We have structural engineers on-site to ensure that they will not be injured, but they are proceeding because they are so motivated and they are taking extraordinary risk on the site every day,” she said.

With searchers using saws and jackhammers to look for pockets large enough to hold a person, Levine Cava said there was still hope of finding people alive.

State Sen. Jason Pizzo of Miami Beach told the Miami Herald he watched as tactical teams of six worked to sift through the debris. He said he saw one body taken in a yellow body bag and another that was marked. They were taken to a homicide unit tent that was set up along the beach.

Many people waited at a reunification center for results of DNA swabs that could help identify victims.

Officials said no cause for the collapse has been determined.

Video of the collapse showed the center of the building appearing to tumble down first and a section nearest to the ocean teetering and coming down seconds later, as a huge dust cloud swallowed the neighborhood.

About half the building’s roughly 130 units were affected, and rescuers used cherry pickers to evacuate at least 35 people from the still-intact areas in the first hours after the collapse. But with 159 still unaccounted for, work could go on for days.

Television video early Friday showed crews fighting flareups of fires on the rubble piles.

Computers, chairs, comforters and other personal belongings were evidence of shattered lives amid the wreckage of the Champlain, which was built in 1981 in Surfside, a small suburb north of Miami Beach. A children’s bunk bed perched precariously on a top floor, bent but intact and apparently inches from falling into the rubble.

The missing included people from around the world: A beloved retired Miami-area teacher and his wife; Orthodox Jews from Russia; Israelis; the sister of Paraguay’s first lady; others from South America.

Argentines Dr. Andres Galfrascoli, his husband, Fabian Nuñez, and their 6-year-old daughter, Sofia, had spent Wednesday night there at an apartment belonging to a friend, Nicolas Fernandez.

Galfrascoli, a Buenos Aires plastic surgeon, and Nuñez, a theater producer and accountant, had come to Florida to get away from a COVID-19 resurgence in Argentina and its strict lockdowns. They had worked hard to adopt Sofia, Fernandez said.

“Of all days, they chose the worst to stay there,” Fernandez said. “I hope it’s not the case, but if they die like this, that would be so unfair.”

They weren’t the only South Americans missing. Foreign ministries and consulates of four countries said 22 nationals were missing in the collapse: nine from Argentina, six from Paraguay, four from Venezuela and three from Uruguay.

The Paraguayans included Sophia López Moreira — the sister of first lady Silvana Abdo and sister-in-law of President Mario Abdo Benítez — and her family.

Israeli media said the country’s consul general in Miami, Maor Elbaz, believes that 20 citizens of that country are missing.

Also missing was Arnie Notkin, a retired Miami-area elementary school physical education teacher, and his wife, Myriam. They lived on the third floor.

“Everyone’s been posting, ‘Oh my God, he was my coach,’” said Fortuna Smukler, a friend who turned to Facebook in hopes of finding someone who would report them safe.

“They were also such happy, joyful people. He always had a story to tell, and she always spoke so kindly of my mother,” Smukler said. “Originally there were rumors that he had been found, but it was a case of mistaken identity. It would be a miracle if they’re found alive.”

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