Hurricane Dean could become a Category Five monster as it gathers force in the Caribbean this weekend, forecasters said.Winds have already reached Category Four speeds of 145mph, claiming the lives of at least three people as it headed towards Jamaica - where about 5,000 Britons are on holiday.

The National Hurricane Center in Miami warned it could achieve the highest category with winds of 150mph before it reaches Mexico on Monday.

In America, Nasa shortened today's spacewalk on the Endeavour shuttle to allow it to return before the storm arrives at the Houston mission control on Wednesday.

Even though the hurricane is unlikely to strike Louisiana, the state declared a state of emergency amidst fears it could repeat the 2005 disaster in which Hurricane Katrina flooded New Orleans.

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The neighbouring state of Texas named Dean an imminent threat.

Dean is the first hurricane of the Atlantic season, which is expected to be unusually active this year.

Banana plantations were flattened, power lines torn down and roofs blown off as the storm ravaged the islands of Dominica, St Lucia and Martinique yesterday.

A 62-year-old man was swept away and drowned when he tried to retrieve a cow from a rain-swollen river in St Lucia.

In Dominica, a woman and her seven-year-old son were killed when a landslide crushed their home as they slept.

Today the hurricane, moving at 18 mph, is due to pass over the flood-prone island of Hispaniola, which is shared by Haiti and the Domenican Republic.

Haitian authorities issued an alert for coastal communities and ordered fishing boats to stay ashore until after the weekend.

Prime Minister Portia Simpson-Miller of Jamaica, where a direct hit is expected tomorrow, ordered shelters opened across the island and called for a halt to campaigning for the Aug 27 elections.

"Let us band together and unite in the threat of this hurricane," the prime minister said.

The Foreign and Commonwealth Office advised against "all non-essential travel" to Jamaica.

The Federation of Tour Operators is closely monitoring the hurricane's progress to see if flights to the island should operate during the weekend, a spokesman said. "It's unlikely there will be any mass evacuation."