Hurricane Irma evacuees are returning to scenes of devastation in the Florida Keys with reports of a quarter of homes destroyed on the low-lying islands.
The latest images show homes torn apart after the storm pummelled the region with winds of up to 120mph (192km/h).
Search and rescue teams are moving through the worst affected areas with emergency supplies of food and water.
US President Donald Trump will visit Florida on Thursday to view the damage caused as Irma tore through the state.
It will be Mr Trump’s third trip related to hurricanes in two weeks and he will be joined this week by his wife Melania, the first lady.
About 90,000 residents returning to the Florida Keys and Miami Beach have been warned that most fuel stations remain closed and mobile phone signals are patchy.
Some residents were allowed into the towns of Key Largo, Tavernier and Islamorada on Tuesday morning.
“Returning residents should consider that there are limited services. Most areas are still without power and water,” authorities in Monroe Country said.
Irma is being linked to at least 18 deaths in the US since it struck as a category four storm on Sunday, including 12 in Florida.
Federal Emergency Management Agency administrator Brock Long said at least 25% of homes in the Keys were destroyed and 65% suffered significant damage.
“Basically, every house in the Keys was impacted,” he said.
Florida Governor Rick Scott said: “So many areas that you would never have thought have flooded, have flooded.”
The storm earlier left a trail of destruction in the Caribbean, where nearly 40 people were killed.
The BBC’s Laura Bicker and Paul Blake on Tortola island say many neighbourhoods have been flattened, and their residents can be seen trying to cook and clean amidst the rubble.
European countries have been boosting relief efforts in their Caribbean territories amid criticism over their response to Hurricane Irma.
French President Emmanuel Macron, who is visiting French islands that took the full force of the storm, said his government had responded with “one of the biggest airlifts since World War Two”.
UK Foreign Minister Boris Johnson is also due to visit the British Virgin Islands and Dutch King Willem-Alexander is touring the Dutch side of St Martin, where at least four people were killed.
“I have seen proper war as well as natural disasters before, but I’ve never seen anything like this,” King Willem-Alexander told Dutch radio on Tuesday.