"Hope springs eternal," he said at a news conference at the nearby St. Regis hotel after meeting privately with affected families and before viewing flowers and posters woven into a fence as an impromptu memorial near the condo ruins.

"The whole nation is mourning with these families. They see it every day on television, they're going through hell," he told reporters. Some relatives had "heartwrenching" questions for him, he said, such as worries over whether they would even have remains to bury or cremate at a funeral.

"I sat with one woman who lost her husband and her little baby boy and didn't know what to do."

Earlier in the day, Biden attended a briefing with local officials, including Governor Ron DeSantis, who is widely seen as a potential Republican presidential candidate in 2024.

Biden, a Democrat, told them he would deliver "whatever you need" and said he expected the federal government would cover the full costs for the county and state and provide temporary housing for survivors. He made a point of saying that the meetings with the governor, an ally of his predecessor, Donald Trump, had transcended party politics.

"There's no disagreement, there's no bickering," Biden said at the news conference. "Everybody is on the same team."

Biden also met with firefighters and other first responders who have been searching for victims at the site.

"I just wanted to say: thank you, thank you, thank you, thank you," Biden told them. He also appeared to refer to the people who rescued his two sons from a car crash that killed his first wife and infant daughter in 1972.

RESCUE EFFORT PAUSED

Rescue workers at the site were instructed to stop just after 2 a.m. on Thursday when movement in the debris raised concerns that the part of the building still standing could collapse, officials said.

"The search-and-rescue operation will continue as soon as it is safe to do so," Miami-Dade County Mayor Daniella Levine Cava said at a news briefing.

Authorities said they have not given up. But nobody has been pulled alive from the wreckage since the early hours of the disaster in the oceanfront town of Surfside, adjacent to Miami Beach.

Miami-Dade County Fire Chief Alan Cominsky said rescuers did hear signs of life during their initial efforts last week.

"They were searching for a female voice, is what we heard for several hours," he said. "Eventually, we didn't hear her voice anymore."

Officials are also keeping a watchful eye on Tropical Storm Elsa, which formed over the Atlantic and could reach south Florida by Monday, potentially hampering search operations.

The Federal Emergency Management Agency has dispatched five urban search-and-rescue teams, each comprising 80 members, to assist in sifting through the rubble, White House spokesperson Karine Jean-Pierre told reporters aboard Air Force One.

DeSantis said workers have removed some 1,400 tons of material from the collapse site.

Thursday's trip is Biden's second visit to the scene of a disaster since he became president in January. In February, he traveled to Texas after a winter storm left millions without power or clean water for days and killed several people.

Investigators have not determined what caused nearly half of the 40-year-old condo complex to crumble in one of the deadliest building collapses in U.S. history.

But a 2018 report prepared by engineering firm Morabito Consultants ahead of a building safety recertification process found structural deficiencies in the 136-unit complex that are now the focus of inquiries.

The Washington Post reported late on Wednesday that the majority of the board of the Surfside condominium, including its president, resigned in 2019, partly in frustration over what was seen as the sluggish response to the report.