SANTO DOMINGO, Dominican Republic (AP) _ After plowing through the northern Caribbean, Hurricane Georges carved into the Dominican Republic on Tuesday, killing 12 people, uprooting trees and causing severe flooding that sent Dominicans and tourists alike fleeing to shelters.

The fatalities brought the death toll throughout the region to at least 21.

The mammoth storm was on a trajectory that could send it crashing into the Florida Keys by late Thursday or early Friday. Authorities urged tourists to leave the island chain, as residents began boarding up windows in anticipation of Georges' fury.

The storm caught the Dominican capital of Santo Domingo almost entirely unprepared Tuesday. Forecasters had expected it to hit only the northern coast, but Georges changed course and headed straight for the tropical capital of 3 million people.

The storm continued churning across the island of Hispaniola and entered the impoverished nation of Haiti, where damages were expected to be severe due to substandard housing and minimal preparation for the hurricane.

So far, Georges has caused extensive damage to several northeast Caribbean islands. Three people were killed on St. Kitts and two on Antigua, before the storm hit Puerto Rico, where at least four people were dead.

The storm caused what is expected to be hundreds of millions of dollars in damage in Puerto Rico, where the entire island lost power and most had their water cut. Tens of thousands took refuge in shelters.

In the capital of San Juan, where almost half the island's people live, downed power lines and trees fell onto flooded roads, making some impassable.

``After the storm is always the worst,'' said Paula Aponte Figueroa, 71, as she swatted at mosquitoes in the musty heat, the roof of her house ripped off by the winds. ``You've got flooding, you've got mosquitoes and I have nowhere to go.''

At 11 p.m. EDT, the eye of Georges was located over the Dominican Republic, 45 miles north-northeast of Port-au-Prince, the capital of Haiti.

Winds had decreased to about 80 mph _ as opposed to 110 mph earlier in the day, and were expected to diminish further until the storm passes over Hispaniola.

Georges also knocked out communications with the U.S. Virgin Islands, where damage was reported as extensive Monday and which President Clinton declared, along with Puerto Rico, a disaster area. Efforts to telephone the U.S. Virgin Islands failed Tuesday. James Witt, the director of the Federal Emergency Management Agency, was reportedly considering flying to St. Croix on Wednesday.

Henry Laskowski, a meteorologist at the National Weather Service in San Juan, said roofs were blown off and trees were felled by winds of over 100 mph on St. Croix, which is part of the U.S. territory, but there were no reports of fatalities.

In the Dominican Republic, where Georges flipped small airplanes and whisked away satellite dishes, the damage was expected to be extensive.

In this poor country where the minimum wage is about $140 a month, the wooden houses that line riverbeds and hillsides were no match for the storm's winds.

President Leonel Fernandez declared an overnight curfew and sent soldiers out on patrol to deter looters.

Ruben Paulino Alvarez, secretary of the armed forces, said 12 people were killed in the Dominican Republic. He said a family of four died when a tree fell on their house in a Santo Domingo suburb; a boy died in the capital when a wall fell on him; another person died in Santo Domingo when a roof collapsed, and four people died in the eastern city of Higuey _ three when a roof fell on them and one from a falling tree.

He did not give details of the other two deaths.

In neighboring Haiti, which shares the western half of the island of Hispaniola, people prepared to battle the hurricane amid even more profound poverty.

The Haitian government has only been able to muster $130,000 for emergency assistance, said civil defense spokeswoman Yolaine Surena. Cars streamed out of the capital, Port-au-Prince, as some headed for cover farther inland.

``We're scared a little, but we have a lot of faith,'' said supermarket clerk Nadine Augustin, 19.

In the Florida Keys, visitors were urged to take airline flights while they were still available, or to leave before the rush by way of the Overseas Highway, the only road linking the 110-mile ribbon of islands.

David Chorney, a meteorologist at the National Hurricane Center in Miami, said there was ``a pretty good probability'' that Georges would hit Florida.

``As far as intensity, it's still too early to tell what it's going to do,'' he said. After crossing the Caribbean islands and getting back over water, he said, ``there's a good chance it could redevelop and strengthen again.''

The strength of the storm was evident as it ripped the roof off the cab of a water tanker truck passing through Santo Domingo, flipping it onto the hood of the vehicle.

Georges also flooded parts of the Dominican capital. One highway overpass normally 22 feet above ground was at water level.

Looters could be seen carrying television sets and microwave ovens on their heads through waist-deep water.

Police Chief Jose Anibal Sanz said officers fired at several people who were looting a shopping center. ``Under no circumstances are we going to allow vandals to take advantage of this misfortune,'' Sanz said.