SURFSIDE, Fla. (AP) President Joe Biden on Thursday offered comfort to the grieving and federal support for the ongoing efforts to search for the missing and rebuild after last weeks collapse of a high-rise condo building along the Florida coastline.

Biden, responding to what appeared to be the deadliest calamity of his young presidency, also met with first responders hunting for survivors among the rubble in Surfside. But underscoring the dangers still present in the search, work was halted before Biden arrived due to concerns about the stability of the section still standing.

Biden and his wife Jill arrived in Florida a week after the collapse of the 12-story Champlain Towers South beachfront condominium killed at least 18 people and left 145 missing. Hundreds of first responders and search-and-rescue personnel have been painstakingly searching the pancaked rubble for potential signs of life. No one has been rescued since the first hours after the collapse.