US rescuers digging through the rubble of a Florida beachfront condo sought to reassure families that they were doing as much as possible to find missing loved ones.
But the crews said they needed to work carefully for the best chance of uncovering survivors four days after the collapse.
As the death rose on Sunday to nine, relatives were growing increasingly desperate for news and worried about the slow progress and dwindling hopes.
Some were taken by bus to a location near the site after families frustrated with the pace of rescue efforts demanded to visit the scene.
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"My daughter is 26 years old, in perfect health. She could make it out of there," one mother told rescuers during a Saturday meeting with family members.
A video of the meeting was posted by Instagram user Abigail Pereira.
"It's not enough," continued the mother, who was among relatives who pushed authorities to bring in experts from other countries to help.
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"Imagine if your children were in there."
More than 150 people remain unaccounted for in Surfside, and authorities and loved ones fear the toll will go much higher.
Scores of rescue workers remained on the massive pile of rubble, searching for survivors but so far only finding bodies and human remains.
No one has been pulled alive from the pile since hours after the collapse on Thursday.
In a meeting with families on Saturday evening, people moaned and wept as Miami Dade Assistant Fire Chief Raide Jadallah explained why he could not answer their repeated questions about how many victims they had found.
"It's not necessarily that we're finding victims, OK? We're finding human remains," Mr Jadallah said, according to the video posted on Instagram.
Every time crews find remains, they clean the area and remove the remains.
They work with a rabbi to ensure any religious rituals are done properly, Mr Jadallah said.
"So the question is, is why is things taking so long?" he said, "What we're doing is making sure that everything is followed to a 'T.'"
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Authorities said their efforts are still a search-and-rescue operation. Alan Cominsky, chief of the Miami-Dade Fire Rescue Department, said they are holding out hope of finding someone alive, but they must be slow and methodical.
"The debris field is scattered throughout, and it's compact, extremely compact," he said.
Debris must be stabilised and shored up as they go.
"If there is a void space, we want to make sure we're given every possibility of a survivor," he said. "
That's why we can't just go in and move things erratically, because that's going to have the worst outcome possible."
So far, he said, they have not come across any voids.
READ MORE: Almost 100 missing after Miami building collapse
A fire in the rubble pile slowed efforts earlier in the weekend, but Miami-Dade Mayor Daniella Levine Cava said it was suppressed on Saturday.
She said six to eight teams are actively searching the pile at any given time, with hundreds of team members on standby ready to rotate in.
She said teams have worked around the clock since Thursday, and there was no lack of personnel.
Teams are also working with engineers and sonar to make sure the rescuers are safe.
"We need to be sure that the pile does not fall on them," she said.
"It does not fall on any possible survivors and we are diligently pursuing that as we do our work."
Crews spent the night digging a trench that stretches 38.1 metres, six metres across and 12.1 metres deep, which, she said, allowed them to find more bodies and human remains.
Earl Tilton, who runs a search-and-rescue consulting firm in North Carolina, said the rescuers in Miami-Dade County were doing an "outstanding job."
Rushing into the rubble without careful planning and execution would injure or kill rescuers and the people they are trying save, said Tilton, who runs Lodestar Professional Services in Hendersonville, North Carolina.
"I understand the families' concerns on this," Mr Tilton said.
If it was my family member, I would want everyone in there pulling rubble away as fast as humanly possible."
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"But moving the wrong piece of debris at the wrong time could cause it to fall on them and crush them."
During past urban rescues, rescuers have found survivors as long as a week past the initial catastrophe, Mr Tilton said.
Florida Governor Ron DeSantis praised the search teams as being "some of the best in the business."
"I'd hope that none of these things would ever happen anywhere, but if something like this happens, the people you would want are Miami-Dade search and rescue," Mr DeSantis said during a Sunday news conference.
"These teams have gone all over the world. These are the people that you want. And they've been there within minutes, and it's been nonstop."
Authorities also sought to assure family members directly that the rescuers were well qualified, telling them during a Saturday meeting that some rescuers had worked on search-and-rescue operations after the Oklahoma City bombing, at the World Trade Centre after the 9/11 attacks and following the Haiti earthquake.
After remains are found, they are sent to the medical examiner.
Authorities are gathering DNA samples from family members to aid in identification.
Late Saturday, four of the victims were identified as Stacie Dawn Fang, 54; Antonio Lozano, 83; Gladys Lozano, 79; and Manuel LaFont, 54.
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