The US is bracing itself for the arrival of Hurricane Ike, which has strengthened to a category two storm as it travels over the Gulf of Mexico.
The storm has already killed more than 70 people in the Caribbean and caused widespread destruction.
In Haiti, the United Nations says about 800,000 people, nearly half of them children, are in temporary shelters.
US President Bush has declared a state of emergency in Texas, where the storm is due to make landfall on Saturday.
Authorities in the US say at least two-thirds of oil and gas production has been stopped in the Gulf of Mexico as a precaution.
The storm has maximum sustained wind speeds of nearly 100mph (155km/h) and meteorologists say it is likely to develop into a major hurricane on Thursday.
Aid appeal
The storm is swirling across the Gulf of Mexico on a projected path towards the Texas coast and is expected to pick up speed.
US National Hurricane Center (NHC) projections show Ike reaching the US coast by the end of the week but say the storm's path could veer.
Louisiana's governor has warned coastal residents to be prepared to move inland.
Hurricane Ike hit Cuba for a second time on Tuesday, causing extensive damage across the country and leaving four people dead - the first storm-related fatalities in the country for several years.
Tens of thousands of buildings have been damaged and crops destroyed and the tourist industry is also likely to be affected, says the BBC's Michael Voss in Havana.
The UN estimates the cost of the damage at between $3bn-$4bn.
Cuba was already reeling from the impact of Hurricane Gustav, which destroyed about 100,000 homes when it hit the island at the end of August.
The NHC has warned that continuing heavy rain over western Cuba could cause "life-threatening flash floods and mudslides" in the mountainous areas.
Ike earlier caused 66 deaths in Haiti and reportedly damaged 80% of the homes in the Turks and Caicos Islands.
Haiti, the poorest country in the Western hemisphere, has endured the onslaught of four tropical storms in a three-week period, causing more than 550 deaths.
The UN has appealed for more than $100m (£57m) in international aid to assist Haiti, where most people already lived on less than a dollar a day.
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