The death toll has risen in the Caribbean following last week's deadly storm
US officials say a quarter of all homes in the Florida Keys have been destroyed as a result of Hurricane Irma.
10 million people in the state are still without power after the storm, after it was hit by winds of almost 200km/h.
Irma also swept through the Caribbean last week, with the death toll there having risen to at least 43 people.
BBC reports that the death toll in the US had risen to 18, including 12 in Florida.
US officials said business owners and residents will start being allowed return to the Florida Keys.
Monroe County authorities warned: "Returning residents should consider that there are limited services. Most areas are still without power and water. Cell service is spotty. And most gas stations are still closed."
Federal Emergency Management Agency (FEMA) administrator Brock Long estimated that 25% of homes in the area were destroyed, while almost two-thirds suffered 'significant' damage.
He warned that 'every house' in the Keys was affected in some way.
The White House has announced that President Trump will visit Florida on Thursday.
Meanwhile, the biggest names in American entertainment yesterday took part in a telethon to raise money for victims of the twin hurricanes which have ravaged the US and Caribbean.
Justin Bieber, George Clooney, Oprah Winfrey, Julia Roberts and Tom Hanks were just some of the stars who appeared in the event, broadcast simultaneously from New York, Los Angeles, San Antonio and Nashville.
The one-hour Hand in Hand: A Benefit for Hurricane Relief was broadcast live at prime time on all of the major US TV networks, as well as online.
The event was originally planned to help victims of Hurricane Harvey in Texas but was expanded after the extent of the devastation caused by Hurricane Irma became clear.
As the show drew to a close, host Billy Crystal revealed that $14m (€11.6m) had been pledged in the hour alone.
Additional reporting by IRN