Hurricane Matthew has left at least 108 people dead in Haiti, the country's interior minister says.
New images from remote and cut off areas in the south-west of the country show scenes of devastation. The hurricane has again been upgraded to a Category Four storm, the second highest hurricane classification, as it heads for the US state of Florida.
Hurricane Matthew - the most powerful Caribbean storm in nearly a decade - is currently pounding the Bahamas, after slicing through Haiti and Cuba.
At least 140 people have died across the region since it first made landfall on Tuesday, Reuters reported, with Haiti suffering the worst losses.
Most of the fatalities were in towns and fishing villages around Haiti's Tiburon peninsula, with many killed by falling trees, flying debris and swollen rivers.
The storm passed directly through the peninsula, driving the sea inland and flattening homes with winds of up to 145 mph (230 kph) and torrential rain on Monday and Tuesday. Hurricane Matthew is already the deadliest Atlantic storm since 2012, when Hurricane Sandy directly killed at least 147 people.
Sandy was a category three storm. Matthew is a category four, after being downgraded from category five - the highest classification.
Category five hurricanes are rare, and not always the most deadly. Circumstances, rather than wind speed, dramatically affect how dangerous a storm is.
In 2005, Hurricane Katrina was a category three when it made landfall in the United States. It left 1,800 people dead, and was the costliest storm in US history with damage estimated at $108 billion (£85bn).
The last category four storm in the Atlantic, Hurricane Joaquin in October 2015, killed 34 people - 33 of which were on board the cargo ship El Faro, which sank during the storm.
At least 130 people were killed in Honduras and Nicaragua during the last category five Atlantic storm - Hurricane Felix - which hit Central America in 2007. Haiti's Interior Minister, Francois Anick Joseph, announced a rapid increase in the death toll on Thursday as aid workers and authorities tried to gauge the true scale of the devastation.
The collapse of an important bridge on Tuesday had left the south-west largely cut off.
"The whole southern coast of Haiti, from the town of Les Cayes to Tiburon, is devastated," Pierre-Louis Ostin told the AFP news agency.
More than 29,000 homes were destroyed in the hard-hit Sud department alone, and more than 20,000 people have been displaced, local authorities said. Across the country, there are some 350,000 in need of assistance, according to the UN Office for the Coordination of Humanitarian Affairs.
Aerial images from the town of Jeremie show hundreds of homes flattened. It was "pretty much wiped out from the seaboard all the way to the cathedral", a radio host in Haiti's capital of Port-au-Prince told the BBC on Thursday. "The devastation that we are seeing is horrible...The town is really in dire straits and it's very, very bad down there."
Early assessments carried out by authorities showed nearly 2,000 homes were flooded and at least 10 schools were damaged across the country, the French Itele website reports.
Haiti's presidential election due this weekend has been postponed because of the hurricane.
The country is one of the world's poorest, with many residents living in flimsy housing in flood-prone areas. Four people also died in the storm in the neighbouring Dominican Republic on Tuesday.