Five days after a building collapsed near Miami in the US state of Florida, the death toll rose from 10 to 11, authorities announced Monday, while 150 people are still missing.

"In the last hours, paramedics have found another victim. The confirmed death toll is 11," Miami-Dade Mayor Daniela Levin Cava said during a Monday evening news conference.

And 150 people are still missing, including dozens of Latin Americans from Argentina, Colombia, Paraguay, Chile and Uruguay.

The mayor confirmed that the search operations among the ruins of the building continue "tirelessly" and "around the clock", and are being carried out by paramedics from Miami-Dade and others from Florida and even from the Israeli Occupation and Mexico who arrived in the past two days.

At dawn on Thursday, the 12-storey building of 55 apartments overlooking the ocean in Surfside, near Miami Beach, collapsed while residents were asleep inside.

The authorities and experts confirmed that the reasons for the collapse of the Champlain Tower are still unknown. But a report on the condition of the building early in 2018 indicated "significant structural damage" as well as "cracks" in the basement, according to documents released by the Surfside City Department on Friday evening.