Fire has spread around the site of the collapsed Miami condo, hampering rescue efforts

• A fire has spread amid the rubble at the site of a partially collapsed building in Florida.
• Firefighters have not been able to identify the source of the fire, Miami-Dade Mayor Daniella Levine Cava said.
• The fire is complicating rescue efforts, Cava said.

A fire has spread along the site of a partially collapsed condo in Florida, hindering rescue efforts, officials said Saturday.

Firefighters have not been able to identify the source of the fire, Miami-Dade Mayor Daniella Levine Cava said during a press conference on Saturday.

"We're facing very incredible difficulties with this fire," Cava said. "It's a very deep fire."

"It's extremely difficult to locate the source of the fire," she added.

Officials also said they would audit some buildings located nearby the condo that collapsed. These buildings are approaching a 40-year review date, and officials said they want to test their safety.

On Friday night, Miami-Dade fire officials urged residents to stay indoors, warning of harmful "smoky conditions."

At least four people are dead after the collapse, which happened early Thursday morning, with more than 150 unaccounted for or missing.

Rescue efforts remain underway. President Joe Biden on Friday signed an emergency declaration for Florida, giving authority to the Federal Emergency Management Agency to coordinate disaster relief. Dozens of fire and rescue units, including FEMA, have since responded to the scene.

Prior to news of the fire, officials said they remained hopeful that they'll rescue survivors from the rubble.

"We will continue search and rescue because we still have hope that we will find people alive," Cava said on Friday at a press conference.

"That is exactly why we are continuing," Cava continued. "That is why we are using our dogs and our sonar and our cameras, everything possible to seek places where there may still be people to be found."

The infrastructure and integrity of the 12-story building is in question, after officials on Friday night released information detailing "major structural damage" to the condo.

Additionally, an engineering consultant found evidence of "abundant" cracking and fragmentation in the building's columns and beams, according to an inspection report from 2018.

The son of a woman who is now missing told CNN she heard creaking noises the day before the collapse. Pablo Rodriguez said his mom called him the day before and said "she had woken up around 3 [or] 4 in the morning and had heard like some creaking noises. They were loud enough to wake her."

And a 2020 study found that the land around the building had shown signs of sinking decades ago.