Hurricane Georges knocked out power and forced residents into shelters in the densely populated Dominican Republic Tuesday, after plowing through Puerto Rico and leaving at least six dead in the northeast Caribbean.

Packing 110 mph winds, Georges' powerful thunderstorms Monday spawned tornadoes, flooded hotels and exploded shop and car windows as it slowly ripped through Puerto Rico. The storm turned trees into missiles, flipped small airplanes, whisked away satellite dishes and forced tens of thousands into shelters. Hundreds of thousands were without water or power."The situation is critical," said Mayor Anibal Melendez of the hard-struck eastern Puerto Rican resort of Fajardo, where dozens of homes lost roofs. The hurricane prevented rescuers from responding to calls for help, and the upscale Conquistador Resort, which overlooks the sea in Fajardo, sustained extensive damage.

More than 80 percent of Puerto Rico's 3.8 million people lost electricity, and more than 70 percent had no water, the government said. Countless roads and highways were choked by fallen trees and poles, dangling power lines, antennas, awnings, tin roofs and other debris.

Police took to the streets of San Juan in force to find the hardest-hit areas and deter looting. Gov. Pedro Rossello met with federal officials Tuesday to plan a disaster response.

"I don't know where we are going to stay," said Andrea Garcia, 33, surveying a mango tree that fell onto the dining room table of her tiny wooden San Juan home.

In the north coast town of Arecibo, National Guard troops rushed to remove residents from alongside the Rio Grande de Arecibo as mountain runoff overflowed its banks.

President Clinton declared Puerto Rico and the U.S. Virgin Islands disaster areas, authorizing immediate release of federal recovery aid. Scores of federal and Red Cross officials mobilized to assess damage, expected to soar well into the hundreds of millions of dollars.

Tourists in the Florida Keys were urged to leave Tuesday as the vulnerable island chain stepped up preparations for Georges.

There was no estimate of how many people might heed the advice and leave. And officials said they would consider beginning the evacuation of some residential mobile-home parks later in the day.

Most computer models at the National Hurricane Center in Miami predicted the storm would affect southern Florida as early as late Thursday.

One of the most powerful storms to hit the Caribbean in years, Georges headed for the Dominican Republic and Haiti, where many of that island's 15 million people live in substandard housing that could leave them exposed to the hurricane's fury.

At noon MDT, Georges' center was about 30 miles east of Santo Domingo.