The death toll in Haiti after Hurricane Matthew tore through the nation has soared to 339, local officials say.
Stanley stands in his destroyed house after the passing of Hurricane Matthew, in Les Cayes, in southwest Haiti. Photo: AFP
Some 50 people were reported to have died in the southern town of Roche-a-Bateau alone.
The peninsula's main city, Jeremie, saw 80 percent of its buildings levelled. In Sud province 30,000 homes were destroyed.
The hurricane has again been upgraded to a Category 4 storm, the second highest hurricane classification, as it heads for the US state of Florida.
The new death toll was given by Haitian officials, Reuters said. On Thursday, a toll of just over 100 was being given.
Hurricane Matthew - the most powerful Caribbean storm in nearly a decade - has pounded the Bahamas after slicing through Haiti and Cuba.
Trees and power lines were reportedly down in the Bahamas but no fatalities were reported.
Most of the fatalities in Haiti were in towns and fishing villages around the southern coast, with many killed by falling trees, flying debris and swollen rivers.
The storm passed directly through the Tiburon peninsula, driving the sea inland and flattening homes with winds of up to 230km/h and torrential rain on Monday and Tuesday.
The collapse of an important bridge on Tuesday had left the south-west largely cut off.
Non-governmental organisations said phone coverage and electricity were down and people were running out of food and water.
Across the country, there were some 350,000 in need of assistance, according to the UN Office for the Coordination of Humanitarian Affairs.
American Red Cross spokesperson Suzy DeFrancis said the first priority was to get phone networks across the country back up and running.
"We will bring in technology to help do that," she said.
"We also have warehouses with relief supplies that we will be distributing. Some of the needs that families may have are kitchen kits so they can cook meals, any kind of hygiene kits and then we are most worried about cholera, so we will be helping to distribute aqua tabs to purify the water."
"I've never seen anything like this," said Louis Paul Raphael, a central government representative in Roche-a-Bateau.
An aerial view shows damaged houses after the passing of the storm in Sous Roche in Les Cayes, southwest Haiti. Photo: AFP
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.
People in Haiti cross the river La Digue in Petit Goave, southwest of Port-au-Prince, where the bridge collapsed during the rains from Hurricane Matthew. Photo: AFP
Cholera risk
Health officials in Haiti warned of a surge in cholera cases after the storm severely damaged water supplies and sanitation systems.
Even before the hurricane, the country was struggling to stem a cholera outbreak that had killed 9000 people since 2010.
The infection is caused by drinking and using contaminated water, and United Nations children's agency Unicef warned children were particularly at risk.
The UN said the hurricane would only make that worse, and 350,000 Haitians needed help, including food and clean water.
World Food Programme country director Carlos Veloso said the aid response was getting under way.
"I can tell you that we have food at the airport ready to be loaded in helicopters from the marines to be sent to the area immediately."
World Vision's Julie Lee said the damage in Haiti was only just becoming clear.
"We are estimating upwards of about a million people have been affected, mainly through flooding, through collapse of houses - complete destruction or partial damage, but we are also seeing a lot of crops and livestock damaged by the hurricane."
Evacuation orders in place for parts of US
The hurricane is strengthening and just hours away from hitting the United States with 11 million people in its path.
As it blew through the northwestern Bahamas on Thursday, its winds increased to 220km/h, the US National Hurricane Center said.
That made it an "extremely dangerous" Category 4 hurricane and it was likely to remain so as it approached the United States, where it could either take direct aim at Florida or brush along the state's coast through Friday night, the centre said.
Florida Governor Rick Scott said people needed to take responsibility for their own safety.
"If an evacuation order is issued for your area, leave immediately. Once the storm comes we can't put first responders at risk to save your life.
"If you make a decision not to leave we cannot send somebody to save you and put your life at risk. think about, you can rebuild your house, rebuild your business, but you cannot rebuild your life.
"If you're reluctant to evacuate, just think about all the people who have been killed," Mr Scott told a news conference on Thursday.
"Time is running out. This is clearly either going to have a direct hit or come right along the coast and we're going to have hurricane-force winds."
Mr Scott, who activated several thousand National Guard troops to help deal with the storm, warned that millions of people were likely to be left without power.
With an expected storm surge of up to 2.7m, he said people should stay away from beaches. "Do not go on the beach," he said, "this will kill you."
The four US states in the path of the hurricane declared states of emergency, a move empowering their governors to mobilise the National Guard.
It was too soon to predict where in the United States Matthew was likely to do the most damage, the Hurricane Center said.
Shelters in Florida, Georgia and South Carolina were opened for evacuees. Federal emergency response teams were coordinating with officials in all four states and stockpiling supplies.
In Washington, White House spokesman Josh Earnest encouraged residents in the path of the storm to heed warnings from local governments about evacuations and seeking shelter.
A woman is carried across La Digue where the bridge collapsed. Photo: AFP
CNN meteorologist Pedram Javaheri said the shallow water in the Caribbean had contributed to the strength of the hurricane.
"Much of these island sitting right there at sea level, very little elevation gain, so if you've ever spent time on the beaches across the Caribbean and particularly in the Bahamas - so very shallow slope here as the water rises.
"So it is a beautiful area of the world to visit, but unfortunately when hurricanes go through these regions there is very little to disturb them and a lot of the time they don't even notice any sort of a land mass in their paths."
- BBC / RNZ / Reuters