While there were no confirmed reports of death or injury so far, an image posted on Miami Beach Police's Twitter account showed a tangle of rubble with debris spilling down from what was left of the balconies of the building in the darkness.
According to the Miami Herald, the 12-story apartment building, part of Champlain Towers, is an oceanside condo built in 1981 with more than 100 units.
CBS News reported that at least one person is dead and people are being extracted from the collapse. "We treated ten people on the site", Burkett said.
Santo Mejil, a local resident, said his wife was an overnight caretaker who was in the complex when it collapsed.
"She said she heard a big explosion".
CNN has reached out to Miami Beach Fire Rescue and the Miami Beach Mayor's office. "It felt like an natural disaster", he told the Miami Herald newspaper, tearing up as his wife called again to say she was being evacuated from the complex.
Authorities in South Florida were responding early Thursday to a "partial building collapse", the Miami-Dade Fire Rescue said.
"May they stay safe while working to save lives", Levine Cava said.
The reason for the collapse is unknown. Search dogs did an initial pass around the wreckage when it was still dark but there were no signs of survivors at that time, the mayor said. The Miami-Dade Police Department said it is investigating the incident.