British holidaymakers travelling to the Caribbean face disruption as Hurricane Dean heads towards popular tourist spots with increasing strength.

Restrictions are now in force on inbound visitors to both Jamaica and the Cayman Islands. The Met Office predicted that Dean could turn into a Category 5 storm - the highest level for a tropical cyclone - within the next three days.

Andy Cooper, director general of the Federation of Tour Operators (FTO), said all FTO members' flights on Sunday to Mexico's Yucatan Peninsula were cancelled. Instead, planes will fly out empty to the region and bring back tourists due to return home.

A MyTravel flight destined for Jamaica has also been delayed for 24 hours.

According to the FTO there are currently just under 4,000 Britons travelling with large tour operators in Jamaica, 9,000 in resorts in the Yucatan Peninsula, and "literally a handful" in the Cayman Islands.

Mr Cooper said: "It is our intention to leave customers there and they will go into shelters in accordance with local procedures."

The Foreign Office is advising against all non-essential travel to Jamaica, where both of the country's international airports are expected to close depending on prevailing weather conditions, the Jamaica Tourist Board said.

The storm, the first hurricane of the Atlantic season, is set to pass directly over Jamaica at about mid-morning Sunday local time, according to weather company MeteoGroup. It is currently travelling at 18mph towards the island, with wind speeds of 150mph and gusts of up to 185mph.

In the Cayman Islands, where the hurricane is expected early on Monday morning, the Government announced that only Cayman nationals and residents can enter the islands until further notice.

Forecasters said Dean could threaten the United States by Wednesday. Texas governor Rick Perry has declared the storm an "imminent threat" and begun full-scale preparations.