Rescue efforts at the site of a partially collapsed Florida condominium building were halted Thursday out of concern about the stability of the remaining structure, officials said.

Search crews that have been atop the pile of rubble for the last week stopped work shortly after 2 a.m., Miami-Dade County Mayor Daniella Levine Cava told a news conference.

The stoppage came on the same day that crews and relatives of those still missing were scheduled to meet with President Joe Biden in a visit that many hoped would provide some measure of comfort to a devastated community.

Crews noticed several expansions in cracks they had been monitoring, including 6 to 12 inches of movement in a large column hanging from the structure “that could fall and cause damage to support columns” in the underground parking garage, Miami-Dade Fire Rescue Chief Alan Cominsky said.

They also noticed movement in the debris pile and slight movement in some concrete floor slabs “that could cause additional failure of the building,” he said.

Officials will work with structural engineers and other experts to “develop options” to continue rescue operations, Cominsky said.

Biden and first lady Jill Biden planned to thank first responders and search and rescue teams. They also planned to meet with the families of victims, White House press secretary Jen Psaki said.

The president’s visit comes a week after Champlain Towers South, a 12-story beachfront condominium building in Surfside, suddenly came crashing down, leaving a pancaked rubble.

Searchers going through the ruins found the remains of six people Wednesday, bringing the number of confirmed dead to 18. The number of residents unaccounted for stands at 145.

Miami-Dade Police Director Freddy Ramirez said he hopes Biden’s visit will be a morale booster for the entire community.

“We’ve had several challenges from weather, sorrow, pain. And I think that the president coming will bring some unity here for our community, support, like our governor, our mayor, all of us together,” he said.

Concerns remained that the still standing portion of the complex could also collapse and work at the site appeared to have paused early Thursday. During a meeting with families Wednesday, Miami-Dade Fire Rescue Assistant Chief Raide Jadallah said officials are concerned about the stability of that portion of the building.

“What we know is that the columns on the east side of the building are kind of, of concern, not compromised, but just right now of concern,” Jadallah said. “Hypothetically, worst-case scenario: If these columns are truly really bad, we are worried they could collapse right back into the parking garage.”

Families were asking if they could add tensions rods but he said structural engineers say that is not possible.

Psaki said the president and first lady also want to make sure that state and local officials have the resources and support they need under an emergency declaration approved by Biden for Miami-Dade. She emphasized Wednesday that the White House is being careful to coordinate with officials on the ground to ensure that Biden’s visit doesn’t do anything to “pull away” from the ongoing search and rescue effort.

State Fire Marshal Jimmy Patronis said he hopes to emphasize to Biden that there is a need for mental health resources to treat rescue workers for post-traumatic stress disorder.

“These guys are so blindly focused on the mission of saving lives, and unfortunately they see things they can’t unsee,” Patronis said.

“We want to make sure that when they ultimately do go home, that we’re giving them the strength … to be able to get back to work without fear of nightmares and challenges.”

(AP)