Families are hoping for miracles as the number of people missing in the Miami condo collapse rose to 159 and the mayor of Surfside expressed fears they would not be found alive.

A dangerous search operation with detection dogs and drones is continuing under the threat of more rubble crumbling and although noises and banging could be heard, there have been no voices.

It’s said it took just 12 seconds for the 12-storey residential condominium to flatten to the ground like a pancake at 1.30am (local time) while many people were believed to have been asleep.

The confirmed death toll stands at four after three more bodies were pulled from the wreckage overnight (local time).

The Champlain Towers South condominium is in Surfside, a barrier island town across Biscayne Bay from the city of Miami.

Video captured by a security camera nearby showed an entire side of the building suddenly folding in two sections, one after the other, at about 1.30am on Thursday, throwing up clouds of dust.

Rubble hangs dangerously from what remains of the collapsed section of the tower in Surfside, Miami. Photo: Getty

Miami-Dade Fire Rescue Assistant Fire Chief Ray Jadallah said rescuers had heard sounds in the rubble overnight but said it could be either falling debris or people tapping.

“We are listening for sounds, human sounds and tapping,” Jadallah said as rescuers use shovels and jackhammers to tunnel under the debris to find pockets where survivors could be.

Officials said the complex, built in 1981, was going through a recertification process requiring repairs, with another building under construction on an adjacent site.

The Champlain Towers South had more than 130 units, about 80 of which were occupied.

The number of people who have been located and declared safe stands at 102.

US President Joe Biden earlier approved an emergency declaration in the state of Florida and ordered federal assistance to supplement state and local response efforts.

“The President’s action authorises the Department of Homeland Security, Federal Emergency Management Agency (FEMA), to co-ordinate all disaster relief efforts,” the White House said on Friday.

Hoping for ‘lots of miracles’

Families are hoping but as time goes on, the chances of finding survivors fades. Photo: Getty

Families have been waiting at a community centre a few blocks away, desperate for information and putting out pleas for help while fearing the worst.

Miami-Dade Mayor Daniella Levine Cava said rescue teams were “incredibly motivated” to find survivors and “we still have hope that we will find people alive”.

However the mayor of Surfside Charles Burkett was concerned about the high number of missing despite the unrelenting search for signs of life.

“It’s heartbreaking because it doesn’t seem to me… that we will find people alive,” Mr Burkett said.

Rachel Spiegel, whose mother Judy Spiegel is missing, said she was “praying for a miracle”.

The last time Ms Spiegel communicated with her mum was on Wednesday night, when her mother excitedly texted her that she had bought a dress online for her granddaughter.

“The dress is in the mail and I just want my mum to give it to her,” Ms Spiegel told CNN, wiping away tears.

Mariela Porras, a friend of a woman who lived in the building with her young daughter and is now missing, said she has not abandoned hope that the two were still alive beneath the rubble.

“I vacillate between hope and I’m heartbroken,” Ms Porras said.

Ms Porras said she has called, texted and visited a reunification centre but has not heard from her friend, a photographer who was working to get a real estate licence.

Missing Australians

Authorities are urgently trying to determine if any Australians were caught up in the collapse amid reports a couple from Melbourne is missing.

Joseph Waks believes an elderly Australian couple he’s known for many years was in the building at the time.

He has not heard from them since the collapse and has been waiting at the scene for updates from police.

“We’re hoping for the best, we’re hoping there’ll be a miracle,” he has told the ABC.

He said the couple was originally from Sydney but later moved to Melbourne and divided their time between Australia and Miami, where they have family.

“They have been in and out of this community for many, many years,” he said.

“It’s devastating. They both became grandparents yet again a few hours before the tragedy. We still cannot believe it.”

Waks said the incident had come as a shock to the “quiet, pleasant, beautiful, lovely, family-orientated neighbourhood” but that residents were pitching in to help each other.

“Everyone’s just coming together: the community, the stores, the people,” he said.

Danny Rivero, a reporter from National Public Radio in South Florida, tweeted on Friday: “We’ve been told many Argentinians and Australians were in the building as well, and that all are unaccounted for. This is an international disaster.”

The Department of Foreign Affairs and Trade said it was aware of reports Australians may have been caught up in the disaster at the Champlain Tower South Condominium.

“The Australian embassy in Washington is closely monitoring developments and making urgent enquiries to determine if any Australians were affected,” it said.

Surfside is a community of 5700 residents with a large Jewish presence.
The Australian Jewish Association has been in contact with a committee member who is in Miami, staying near the collapsed building.

There are no reports so far of any Australian Jews being caught up in the disaster, a spokesman for the association told AAP.

-with AAP