Rescue teams hopeful on finding survivors among 'voids' in Florida condo rubble as time expires

Rescue teams are optimistic the Miami-area condominium that partially collapsed last week still has some pockets of space – known as "voids" – in which they can find survivors, despite the search operation now entering a fifth day.

Andy Alvarez, a deputy incident commander with Miami-Dade Fire Rescue, told ABC’s "Good Morning America" on Monday that rescuers have been able to find some voids inside the wreckage, mostly in the basement and parking garage areas.

"We have over 80 rescuers at a time that are breaching the walls that collapsed, in a frantic effort to try to rescue those that are still viable and to get to those voids that we typically know exist in these buildings," said Alvarez, according to the Associated Press. 

However, the last rescue of a living person at the Surfside, Fla., condo was Thursday, just hours after the collapse.

More than 150 people are still missing.

The death toll rose by just four people Sunday, bringing the total to nine since a tower of the Surfside condominium, north of Miami, collapsed early Thursday morning, the wire service also reports. 

Engineers and others trying to learn what caused the incident appear to be focusing on possible structural problems or deficiencies.

The 12-story building collapsed just days before a deadline for condo owners to start making steep payments toward more than $9 million in repairs that had been recommended nearly three years earlier, in a report that warned of “major structural damage.”

Authorities on Sunday identified the additional four people that had been recovered as Leon Oliwkowicz, 80; Christina Beatriz Elvira, 74; Ana Ortiz, 46; and Luis Bermudez, 26. The number of people left unaccounted for was 152, said Miami-Dade Mayor Daniella Levine Cava.