A search and rescue operation is underway after a huge part of a 12-story building collapsed in Surfside, Florida, a town just north of Miami Beach. Around 2 am people in the area say it was felt like there was an earthquake, or “a big explosion.” One person is confirmed dead and 10 others injured.

Rescuers have pulled at least 35 people from the rubble. 99 people who were “supposedly residing” in the building have not yet been accounted for, Miami-Dade County Commissioner Sally Heyman said on CNN.

The complex has 100 units and at least 30 are believed to have collapsed. The Miami Herald quotes Surfside Commissioner Eliana Salzhauer as saying,

Salzhauer said the building was beginning its 40-year recertification, and the building’s roof was being redone, but it is unknown if any construction activity contributed to the disaster.

Miami-Dade Mayor Daniella Levine Cava said the county’s Fire and Rescue Department was taking lead in rescue operations, with city and county first responders on the scene. She said “cause unknown” as to the partial collapse of the building.

Surfside Mayor Charles Burkett added, “The problem is the building has literally pancaked … It’s heartbreaking because it doesn’t mean, to me, that we’re going to be successful, as successful as we want to be, to find people alive.”

Watch more from the Today show above.