A major rescue operation is underway after a 12-storey building partially collapsed in Miami during the night.

More than 80 fire and rescue units are currently at the scene.

While there was no official comment on how many people might have been hurt, a firefighter on the scene could be heard saying there were multiple casualties, the Miami Herald reports.

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.

"MBPD and @MiamiBeachFire are assisting the Town of Surfside at a partial building collapse located at 8777 Collins Avenue in Surfside, Florida. Multiple police and fire agencies from across Miami-Dade are assisting," the police said.

The reason for the collapse is unknown.

A huge rescue operation is under way in Miami-Dade County, Florida, after a 12-storey building partially collapsed during the night.

More to follow.