U.S. President Joe Biden approved early Friday an emergency declaration in the state of Florida after a beachfront condominium building partially collapsed outside Miami, killing at least one person and injuring 10. Dozens more are unaccounted for.

Biden ordered federal assistance to bolster the state and local response efforts in coordination with the Miami local government, The Guardian said.

Miami-Dade County officials are currently conducting an investigation into the Champlain Towers South Condominium collapse, where hundreds of fire and rescue personnel scoured through tons of rubble.

Miami-Dade police chief Alfredo Ramirez said 99 people remained missing, and that 53 condominium residents were rescued or otherwise accounted for.

"The building is literally pancaked," Surfside Mayor Charles Burkett said in quotes by The Associated Press.

"That is heartbreaking because it doesn't mean, to me, that we're going to be as successful as we wanted to be in finding people alive," the mayor said.

Florida Gov. Ron DeSantis said officials were "bracing for some bad news just given the destruction that we're seeing."

DeSantis has declared a state of emergency in Miami-Dade County in response to the catastrophe.

 Florida chief financial officer Jimmy Patronis said he was deeply moved by the image of a bed near the now-exposed top of the building. "Somebody was probably sleeping in it," he said.

What caused the 40-year-old building to collapse remains unclear.

Video footage posted online showed a big portion of the building reduced to rubble, with the condominium's interiors exposed.

Hundreds of rescuers used sonar cameras and specially trained dogs to scour the rubble for survivors.

They detected sounds of banging and other noises, but no voices coming from the tons of debris.

A man said his calls to missing loved ones had gone unanswered.

"I think they're gone," he told CBS. "I don't want to be pessimistic, but we've been calling them nonstop with no reply."

Search rescuers tunneled from an underground car park below the building as night fell in an effort to reach victims.

Officials say the rescue efforts are dangerous as further rubble could collapse on top of them.

Meanwhile, hotels opened to some displaced residents and deliveries of food, medicine and other essentials were being hastily arranged, DeSantis said.