The storm, the worst to hit the region in decades, has already killed at least 29 people in Grenada, Venezuela, the Dominican Republic, Jamaica and Tobago, and triggered panic buying and mass evacuations in parts of Cuba and Florida.

Twenty-three-foot (seven-meter) waves slammed the coastline of this mountainous, verdant Caribbean island nation of 2.7 million, where a state of emergency was declared at midday Friday.

Ivan's eye, around which its worst winds whirl, did not make landfall in Jamaica, which likely would have made the destruction even worse.

An elderly woman and a child were confirmed killed in the storm, which has triggered widespread flooding, O'Neil Hamilton, a Jamaican government spokesman in Washington, told AFP.

Electricity was shut down across the island to protect the power grid, and rivers overflowed, sweeping away homes and flooding neighborhoods, with waist-high waters roiling with tree branches, boulders and debris. There were reports of scattered looting and arson in Jamaica's crime-plagued capital, Kingston.

"There is widespread damage across Jamaica, roofs lifting everywhere and suburban residences around Kingston have been deeply affected, there is structural damage, ... power lines, live wires on the ground," Hamilton said.

More than 9,000 persons have been evacuated to shelters, he said.

Packing winds of 145 miles (230 kilometers) per hour, at 1800 GMT Ivan's center was 40 miles (70 kilometers) west-southwest of the western tip of Jamaica and 170 miles (270 kilometers) east-southeast of Grand Cayman, the US National Hurricane Center said. Ivan should resume a west-northwest track near eight miles (13 kilometers) per hour later Saturday, it added.

Already a strong Category Four system out of a maximum of five, "some fluctuations in strength are expected but Ivan could become stronger during the next 24 hours," the center warned.

"Storm surge flooding of five to eight feet (1.5 to 2.4 meters) above normal tide levels, along with large and dangerous battering waves, are occurring primarily along the south coast of Jamaica," the US center added.

"Rainfall amounts of eight to 12 inches, possibly causing life-threatening flash floods and mudslides, can be expected along the path of Ivan," it noted.

"Coastal storm surge flooding of 20 feet (six meters) and locally higher above normal tide levels along with large and dangerous battering waves can be expected near and to the east of where the center makes landfall in Cuba.

Ivan was pointed next at Cuba and the Florida Keys, the southern string of causeway-linked islands where mandatory evacuation was ordered, affecting some 80,000 people.

Jamaican authorities pleaded for 500,000 people to leave coastal areas most at risk from the massive storm, which has already killed 17 in Grenada, two in Jamaica, five in Venezuela, four in the Dominican Republic and one in Tobago.

The tiny spice island of Grenada, population 100,000, suffered catastrophic damage in the storm, according to Prime Minister Keith Mitchell.

Up to 90 percent of buildings on the island were damaged, crops were destroyed and tourist resorts were in ruins. Looting and sporadic violence followed in the wake of the storm, prompting the United States to organize an evacuation of some 1,500 of its citizens living there.

In Grenada about 60,000 people are believed to be homeless, with 5,000 to 8,000 people staying in 47 emergency shelters, the Caribbean Disaster Emergency Relief Agency (CDERA) said. "The Caribbean Disaster Relief Unit is now operational at both the air and sea ports and responsible for managing all incoming relief supplies" for Grenada, CDERA said.

In Cuba, where Ivan was due to hit Sunday, authorities rushed Saturday to evacuate some two million people from their homes, shut down the railroad and ports and ready bomb shelters as refuges from Ivan.

A hurricane warning was in effect for Cuba from the western province of Pinar del Rio east to Ciego de Avila including the isle of Youth, the US center said. That would also include the densely populated capital, Havana, with more than two million people and fragile, poorly maintained housing stock.

Waterlogged Florida already has been socked by Hurricanes Charley and Frances in the past few weeks and is expected to feel Ivan's wrath in a matter of days.