Searchers worked early on Sunday to find more than 150 missing residents amid the rubble of a Florida condo building that collapsed three days ago as questions arose about the tower's structural integrity.

The death toll rose to five on Saturday after emergency workers found a victim in their methodical search of the site in Surfside, a shore town near Miami, Miami-Dade County Mayor Daniella Levine Cava said during an evening news briefing.

-Our top priority continues to be search and rescue and saving any lives that we can- Levine Cava said.

Workers also found some human remains; three other victims were identified and their family members notified, she said.

Officials said they harbored hope that some of the 156 people unaccounted for might be alive. Firefighters on Saturday made progress on a smoldering fire and smoke beneath the rubble of the 40-year-old building, allowing rescuers to search with fewer limitations, officials said.

Aided by dogs, infrared scanning and heavy equipment, rescuers hope that people can survive in air pockets that may have formed in the debris. 

-The biggest thing now is hope- Fire Chief Alan Cominsky said. "That's what's driving us. It's an extremely difficult situation."

A 2018 report showed that an engineer found evidence of major structural damage beneath the pool deck and "concrete deterioration" in the underground parking garage of the 12-story oceanfront condominium.