The death toll in the Surfside Miami condo collapse has risen to 18 as 145 people remain missing, one week after the tragic event.

The death toll rose to 18 on Wednesday and includes two children, 4 and 10, according to reports.

“Any loss of life, especially given the unexpected, unprecedented nature of this event is a tragedy,” Miami-Dade County Mayor Daniella Levine Cava said. “But the loss of our children is too great to bear.”

Search and rescue operations remain underway, and President Joe Biden is expected to visit the grieving community Thursday.

“As we await @POTUS‘s arrival, I want to reassure the public that his visit will have no impact on our search & rescue mission,” the mayor assured Thursday morning.

“We’re deeply grateful that our community remains a top priority for the president as he continues to provide the full support of the federal government,” she added:

However, search and rescue operations were reportedly paused in the early morning hours on Thursday due to “structural concerns.” Cava said officials are doing “everything we can to ensure that the safety of our first responders is paramount and to continue our search-and-rescue operation as soon as it’s safe to do so.”

“The only reason for this pause is concerns about the standing structure,” she said, assuring the pause has nothing to do with the president’s visit. “We’ve already informed the families this morning who are waiting and waiting about this development.”

An April letter from the president of the Champlain South Towers condo association reveals ongoing concerns over the condition of the 40-year-old building, outlining the need for millions of dollars in assessments.

At the time, President Jean Wodnicki cautioned that concrete damage observed in the 40-year-old building could “multiply exponentially over the years,” also noting “observable damage” in the April letter.

“When you can visually see the concrete spalling (cracking), that means that the rebar holding it together is rusting and deteriorating beneath the surface,” she wrote.

“The concrete deterioration is accelerating. The roof situation got much worse, so extensive roof repairs had to be incorporated,” she continued.

Florida Gov. Ron DeSantis (R) has since called for investigators to closely examine the “warning signs” seen prior to the building’s collapse.

“There did appear to be some warning signs on this one. So we’re going to have to go through that,” he said:

When you see something like that and people were raising the concerns and it was basically said ‘oh don’t worry about it,’ and look I mean maybe they had a basis for saying it ultimately wasn’t going to be and maybe we’ll find that out, but it sure seems like in hindsight now that those were things that potentially could have been potentially addressed.

The National Institutes of Standards and Technology (NIST) is sending a team comprised of six scientists and engineers to “collect firsthand information on the Champlain Towers South collapse that will be used to determine if an investigation or study will be conducted,” according to NIST spokeswoman Jennifer Huergo.

Notably, the agency was also tasked with investigating the collapse of the World Trade Center.