The death toll from the collapse of a Florida beachfront apartment building has risen to nine as search-and-rescue efforts continue, a local official has said.

One person died in hospital and workers had pulled four more bodies from the wreckage, Miami-Dade mayor Daniella Levine Cava said on Sunday.

Scores of rescue workers remained on the massive pile of rubble, working to find survivors among the more than 150 people who remain unaccounted for following Thursday’s building collapse in Surfside.

Four of the dead had been identified and next of kin notified, the mayor added.

Four days after the collapse, authorities and loved ones fear the death toll will rise much higher.

Rotating teams of rescuers used heavy machinery and power tools to clear the rubble from the top and tunnel in from below at Champlain Towers South.

Surfside mayor Charles Burkett sought to assure families that rescuers were working nonstop.

“Nothing else on our mind, with the only objective of pulling their family members out of that rubble,” he told ABC’s This Week.

“We’re not going to stop doing that – not today, not tomorrow, not the next day. We’re going to keep going until everybody’s out.”

Mr Burkett said a city official had led a cursory review of the nearby Champlain Towers North and Champlain Towers East buildings but “didn’t find anything out of the ordinary”.

The news came after word of a 2018 engineering report that showed the Champlain Towers South building, which was built in 1981, had “major structural damage” to a concrete slab below its pool deck that needed extensive repairs, part of a series of documents released by the city of Surfside.

Further documentation showed the estimated cost of the repairs would total more than nine million US dollars (£6.5 million). That included more than 3.8 million US dollars (£2.7 million) for garage, entrance and pool remediation and nearly 3.2 million US dollars (£2.3 million) for fixes to the exterior facade.

While officials said no cause for the collapse early on Thursday had been determined, Florida governor Ron DeSantis said a “definitive answer” was needed in a timely manner.