SURFSIDE, July 4 (AP) - The partially collapsed Miami-area condominium where 24 people are confirmed dead will be demolished on Sunday (Jul 4) night, ahead of the possible arrival of Tropical Storm Elsa, officials said.

Eighty per cent of the drilling work was complete, and the remaining structure could come down as soon as Sunday night, Miami-Dade Assistant Fire Chief Raide Jadallah told relatives of those missing in the collapse.

Jadallah praised the speedy work of the demolition crews and drew applause from families eager for the search to restart when he said the implosion could happen sooner than initially expected. No one has been rescued alive since the first hours after the Jun 24 collapse.

"The demolition will take place tonight between 10 pm and 3 am (local time)," Miami-Dade County Mayor Daniella Levine Cava told reporters on Sunday.

The search-and-rescue mission at the Surfside building was suspended on Saturday afternoon so workers could begin the drilling work.

Jadallah said the suspension was a necessary safety measure because the drilling could cause the structure to fail, but a family member could be heard calling that news “devastating".

Once the structure is demolished, the remnants will be removed immediately with the intent of giving rescuers access for the first time to parts of the garage area that are a focus of interest, Jadallah has said. That could give a clearer picture of voids that may exist in the rubble and could possibly harbour survivors.

“Once this building is down, it’s going to be a green light, full speed ahead, maximum effort to pull these victims out and reunite them with their family,” Surfside Mayor Charles Burkett told CBS’ Face the Nation.

So far, rescuers have recovered the remains of 24 people, with 121 still missing. The Miami-Dade Police Department on Saturday night added Graciela Cattarossi, 48, and Gonzalo Torre, 81, to the list of those confirmed dead.

Officials began considering the demolition at Champlain Towers on Thursday when parts of the remaining building shifted, endangering rescuers and prompting a 15-hour suspension in their work.

As of Sunday afternoon, Tropical Storm Elsa was off the coast of Cuba with winds of 95kph. After moving across Cuba later on Sunday and Monday, the storm was forecast to approach western Florida on Tuesday or Wednesday.

Instead of the usual fireworks and flag-waving parties, beachside communities in the area have planned more subdued events for the Fourth of July. Miami Beach cancelled its Independence Day celebrations.

Investigators have not determined what caused the 40-year-old complex to collapse on Jun 24. A 2018 engineering report found structural deficiencies that are now the focus of inquiries that include a grand jury examination.

All residents of another building, Crestview Towers in North Miami Beach, were told on Friday to leave immediately after engineers found serious concrete and electrical problems, officials said.

The move was considered urgent because of the approach of Elsa, North Miami beach city manager Arthur Sorey said, adding that the building's owners had not yet begun a mandatory safety recertification process required 40 years after it was built.

"It's definitely not an easy decision," Sorey said. "It's just the right thing to do during these times. It's uncertain what's going to happen with the storm."