Miami-Dade Mayor Daniella Levine Cava said another body was recovered overnight from the site of a collapsed building, bringing the death toll to 10.

A further 151 people who may have been in the building remained unaccounted for, she said.

"The search and rescue operation continues," she told a news conference Monday.

Rescue workers digging for a fifth day into the remnants of a collapsed Florida condo building stressed Monday that they could still find survivors in the rubble, a hope family members clung to even though no one has been pulled out alive since the first hours after the structure fell.

Their families rode buses to a nearby site to watch the intense rescue effort, which included firefighters, sniffer dogs and search experts using radar and sonar devices.

(With input from agencies)