The terrifying storm packed winds of up to 255 kilometers (160 miles) per hour as it churned toward Jamaica where the authorities ordered the population to rush to take emergency precautions.

Ivan has increased in strength to become a top category five storm on the five level Saffrir-Simpson scale.

Twelve people were confirmed killed on Grenada and the toll is expected to climb, the Caribbean Disaster Emergency Response Agency (CDERA) said. A Trinidad radio station FM 95.5 said there were 24 dead in Grenada alone, but that was not immediately confirmed.

There were four dead in Venezuela, according to the national authorities, and one in Tobago.

In the Dominican Republic, four youths drowned Thursday in rough surf churned by Ivan, civil defense officials said. The National Emergency Committee declared the Dominican Republic's south coast on maximum alert.

At 1800 GMT the center of the storm was about 360 miles (580 km) southeast of Kingston, the capital of densely populated Jamaica, the National Hurricane Center in Miami said.

"Ivan continues to be extremely dangerous heading for western Caribbean sea," the center said.

Storm surge flooding of 0.9 to 1.5 meters (three to five feet) above normal tide levels, along with large and dangerous battering waves, could be expected near the center of Ivan in the hurricane warning area, the US center noted.

Rainfall amounts of 12-18 centimeters (five to seven inches), possibly causing life-threatening flash floods and mudslides, can also be expected, it added.

The deadly storm, which devastated Grenada, was moving toward the west-northwest near 15 mph (24 kph) a track that was expected to continue for the next 24 hours, the center said. On this track the hurricane will near Jamaica on Friday, it added.

Grenada, a tiny island nation of 90,000 inhabitants, was 85 percent destroyed by the storm, according to Prime Minister Keith Mitchell. Power lines were down and hundreds of people have taken refuge in shelters.

Mitchell's official residence was destroyed and the prime minister took shelter on a British navy frigate, HMS Richmond.

"We have really taken a tremendous hit in every respect," Mitchell told BBC radio by telephone.

"You are talking hundreds of millions of dollars of damage," he said. "I have declared the country a national disaster and I have contacted our international friends and indicated that."

He said the main prison had been destroyed and all the inmates had escaped.

British sailors from HMS Richmond and the supply vessel HMS Wave Ruler, were helping the emergency operation in Grenada, Britain's Defence Ministry said. The two ships were on patrol in the Caribbean.

Grenada is a former British colony and remains a member of the Commonwealth with Britain's Queen Elizabeth II as its head of state.

"This is the biggest single-island disaster" that the CDERA has responded to, "because almost all of the island is wrecked," CDERA spokesman Terry Ally told AFP from Bridgetown.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.