Originally Published: 28 JUN 21 02:59 ET

Updated: 28 JUN 21 12:35 ET

By Hollie Silverman and Holly Yan, CNN

(CNN) -- Another victim was found in the rubble of the Florida condo collapse, raising the death toll to 10, Miami-Dade County Mayor Daniella Levine Cava said Monday.

The number of people unaccounted in Surfside has decreased to 151, and the number of people who have been accounted for has increased to 135, she said.

Florida State Fire Marshal Jimmy Patronis said rescue workers are working 12-hour shifts to try to find survivors.

"They're working 12 hours at a time, midnight to noon, noon to midnight," Patronis said Monday.

"They come from Tallahassee, they come from Orlando, they come from Tampa, they come from Israel, they come from Mexico, they come from Jacksonville, they come from Fort Myers."

While families endure a fifth day of anguish waiting to hear word of their loved ones, officials near the condo collapse are scrambling to prevent such catastrophes from happening elsewhere.

"Everyone needs to know what is happening in every single community here, especially on the coast of Florida," said said Larisa Svechin, acting mayor of Sunny Isles Beach -- about 5 miles north of Surfside.

"We are immediately putting in plans to check 59 buildings that are either at the 40-year mark or have just went through the 40-year recertification."

Svechin joins the mayors of Miami and Boca Raton in announcing new plans for condo safety after the disaster in Surfside, where 55 units of Champlain Towers South crashed to the ground Thursday.

The search has been dangers, as rescuers have been stymied by a fire and the constant threat of further collapse.

"We know time is of the essence," Maggie Castro of Miami-Dade Fire Rescue said Monday.

"We're still in a rescue mode, but as you can imagine, we're starting to understand that it's going to be less likely that we're going to be finding survivors."

Some frustrated families have channeled their anger toward search officials, Castro said.

"They're looking for someone to blame. There is no one they can blame at this point. The emotions have to go somewhere. We understand that," Castro said.

"We've asked the families that if you need to vent, you (can) vent at us."

Families who want to visit the site of the collapse will be brought in by bus Monday afternoon, officials said.

Why the search is so dangerous

Any wrong move could imperil not just rescue workers, but also potentially survivors trapped in the rubble, retired Miami-Dade assistant fire chief Pete Gomez said.

"You're de-layering all the debris up top, and you have to be very careful with it," Gomez said.

Removing pieces can affect other pieces, and rescuers "don't want to cause more damage if they are in fact alive there."

Over the weekend, rescue workers completed a 40-foot-deep trench in hopes of finding survivors.

Searchers were hoping to find voids -- or spaces where survivors might be safely trapped.

But the scene was "horrific," Miami-Dade Fire Rescue Chief Alan Cominsky said Sunday.

"We don't have the voids that we are hoping for," he said. "We are still looking. So that's what I mean by horrific. It's just a difficult, difficult situation."

The mayor said rescuers are using sonar, cameras and canines to try to find anyone beneath the rubble.

An international effort

More than 400 rescue workers are assigned to the search, the fire chief said.

At any given time, "I think we have over 200 people working on that debris site," he said Sunday.

"It's a strategic process. We can't have one squad working right on top of another. So we have to space out. We have to have different components."

A rescue team from Mexico is expected to arrive Monday, Surfside Mayor Charles Burkett said.

And a team of 10 rescuers from Israel arrived Sunday morning, Kevin Guthrie, director of the Florida Division of Emergency Management, told CNN.

They went to the collapse scene and "were on the pile almost all day," Guthrie said

'There are no words'

Of the 10 people killed, eight have been publicly identified.

Stacie Fang, 54, was the first victim identified Friday. She was the mother of Jonah Handler -- the boy who was pulled from the rubble alive, her family said.

"There are no words to describe the tragic loss of our beloved Stacie," the family said in a statement.

"The many heartfelt words of encouragement and love have served as a much needed source of strength during this devastating time."

Officials identified three victims Saturday: Antonio Lozano, 83, Gladys Lozano, 79, and Manuel LaFont, 54.

Four more victims were identified Sunday: Leon Oliwkowicz, 80; Luis Bermudez, 26; Anna Ortiz, 46; and Christina Beatriz Elvira, 74.

One victim has not yet been identified by authorities.

"The process of identifying these victims is very difficult," Levine Cava said.

"We're going to be relying on DNA testing. And that is why we've already been gathering DNA samples from the family members. So they have all participated and provided DNA to assist us in the investigation," the mayor said.

"This allows us to do rapid DNA testing on-site for bodies."

Those missing are from at least nine countries, including six Latin American countries, and multiple faith communities.

The Greater Miami Jewish Federation offered to help community members with arranging funeral and burial services. In the Jewish tradition, burials are completed within days after death, but some victims might not be recovered in the coming days.

Structural engineers reported issues

A 2018 report by the structural engineering firm Morabito Consultants "detailed significant cracks and breaks in the concrete," the firm said in a statement Saturday.

The report didn't say whether the structure was at risk of collapse, but the group said it provided an estimate to "make the extensive and necessary repairs" to the condo association.

Morabito was retained by the condominium association again in June 2020 for the building's 40-year repair and restoration process, according to the statement.

The firm said it "exclusively provides" engineering consulting services and does not provide construction-related services.

"We are deeply troubled by this building collapse and are working closely with the investigating authorities to understand why the structure failed," Morabito Consultants said.

According to NPR, Rosendo Prieto, who worked as the town's building official at the time, assured residents of Champlain Towers South that their building was "in very good shape" at a November 2018 meeting. NPR cited minutes from the meeting it obtained.

Two days before the meeting, Mara Chouela, a member of the condo board, forwarded a copy of a structural engineer's report to Prieto that warned of "major structural damage," according to an email released by the town on Saturday.

"Structural engineer report was reviewed by Mr. Prieto," the minutes cited by NPR said, in an apparent reference to the 2018 report from structural engineer Morabito Consultants. "It appears the building is in very good shape," the minutes noted, according to NPR.

Prieto no longer works for Surfside and currently serves as the interim building official for Doral, another city in Miami-Dade County, according to the Doral website and a county document. Prieto has not responded to requests for comment from CNN.

In 2020, a structural engineer who inspected Champlain Towers South saw cracks and deterioration, but was not alarmed, the engineer told CNN on Monday.

"I saw cracks in the stucco façade. I saw deterioration of the concreate balconies. I saw cracks and deterioration of the garage and plaza level. But those are all things that we are accustomed to seeing, and that's why our job exists -- to maintain and repair the buildings," engineer Jason Borden said.

Borden said nothing he saw during his hourlong inspection alarmed him. He said the observations were typical of coastal buildings of that age, and what he saw was consistent with the nature of reinforcing steel and concrete over time.

But he said these factors can become a danger when they are not maintained or repaired.

When asked about recent speculation that collapse may have started from the bottom, Borden said in that scenario, "the most likely or the most common would be the failure of a column."

"The columns are one of the most robust parts of the building. They are designed to hold up the entire building. So something had to have happened to a column," he said.

Residents raised concerns over tremors during construction of nearby building

Eliana Salzhauer, one of three Surfside town commissioners, said survivors of the collapse she encountered said had they felt shaking during construction on a nearby building in recent years.

Salzhauer said some of the survivors told her they were bothered by the shaking of their building that occurred while a high-rise that was was under construction next door. They told her there was shaking, cracking and water leaking in the garage, she said.

"They were very traumatized and shook up," Salzhauer said, adding she heard people saying the building "was shaking all the time," during the construction.

Salzhauer also said the 2018 report completed by structural engineers was alarming.

"In hindsight, reading that report is very damning. You read that report you go, 'My god. How could they miss this?'" Salzhauer said.

Magaly Ramsey, daughter of missing Magaly Delgado, said her mother had been concerned about shaking from the nearby construction.

"When the other building beside it, which is relatively new, was being built, she did complain of a lot of tremors and things that were being done to the other building that she sometimes was concerned what may be happening to her building," Ramsey said.

And in an email to Prieto in 2019, condo board member Chouela said she was concerned the nearby construction was "digging too close to our property."

"We have concerns regarding the structure of our building," sh wrote.

Other cities call for more oversight on buildings

The city of Miami sent a letter Friday urging new inspections on buildings that are over six stories and more than 40 years old, city spokesperson Stephanie Severino said.

The letter asks for those buildings to undergo inspection by a qualified structural engineer, with any potential structural problems reported withing 45 days.

On Sunday, Boca Raton Mayor Scott Singer said his city is creating "more stringent standards for certifications of buildings" following the Surfside collapse.

"Our building staff has been working with other jurisdictions to determine the best practices," Singer said.

"A number of our condos have been working on comprehensive restorations. We can expect more of these efforts and increased steps to ensure the safety and welfare of our residents."