President Joe Biden and first lady Jill Biden will travel to Surfside, Florida, on Thursday to visit with the families of victims of the collapsed Miami-area condominium tower, the White House said.

Mr Biden has offered federal help and extended his concerns to the community as people “grieve their lost loved ones and wait anxiously as search and rescue efforts continue”, as he said in one tweet.

“They want to thank the heroic first responders, search and rescue teams, and everyone who has been working tirelessly around the clock and meet with the families who have been forced to endure this terrible tragedy waiting in anguish and heartbreak for word of their loved ones,” White House press secretary Jen Psaki said.

The slow work of sifting through the remnants of the collapsed building stretched into a sixth day Tuesday.

Two additional bodies were found Monday, raising the count of confirmed dead to 11.

That leaves 150 people still unaccounted for in the community of Surfside.

No one has been found alive since hours after the collapse on Thursday.