PROVIDENCIALES, Turks and Caicos - A strengthening Hurricane Ike loomed over this low-lying island chain Saturday as a dangerous Category 4 storm, prompting thousands of people to evacuate while those staying behind hunkered down and hoped for the best.

As the massive gray wall of clouds approached from the east, people poured into the main supermarket in Providenciales, expecting that power would be knocked out and that food would suddenly become scarce.

Shopkeepers and homeowners covered windows with plywood. Boats were hauled ashore or secured with multiple anchors.

"I am very, very nervous," said John Moore, a fishing boat captain, as he tied down his 61-foot vessel in a Providenciales cove. "It looks like it might go right over us, so that's not a good picture."

Ike's eye was about 90 miles (145 kilometers) east of Grand Turk Island Saturday afternoon. It was moving west-southwest about 15 mph (24 kph). The U.S. National Hurricane Center said the storm's maximum sustained winds were 135 mph (215 kph).

The governments of the Bahamas and Cuba issued hurricane warnings.

Forecasters say the storm is likely to strengthen as it approaches southern Florida by Monday.

The approach of the hurricane also raised alarm in Haiti, where aid officials feared it could worsen deadly flooding. And Cuba, still recovering from a devastating hit by Category 4 Hurricane Gustav last month, was directly in Ike's projected path.

Cuba's communist government warned people to be ready to take emergency action, but hotels along its northern coast said they had not yet started evacuating foreign guests.

The storm was not expected to affect Saturday's World Cup soccer qualifier between the United States and Cuba in Havana.

U.S. military commanders at the Guantanamo Bay Navy base in southeast Cuba were coordinating storm preparations and securing anything that might be carried by the wind, said Navy Petty Officer 1st Class Robert Lamb. The U.S. base holds some 255 men suspected on links to the Taliban and al-Qaida in hurricane-proof cells.

Turks and Caicos Premier Michael Misick said his government opened a half dozen shelters and brought in an emergency food shipment.

"We're still praying that the storm will make a northerly turn and we will be spared, even a little bit," Misick told The Associated Press. "It's difficult to predict a storm of this magnitude."

Turks and Caicos and the neighboring Bahamas are close to sea level and are vulnerable to flooding from rain and storm surge.

To reach Haitian immigrants, many of them illegal, the government broadcast emergency messages in Creole and told law enforcement figures not to enforce immigration laws during the storm.

"At a time of disaster, the last thing on our mind is whether you are legal or not," Misick said. "The important thing is to save lives."

The airport in Providenciales closed after thousands of tourists and longtime residents of the typically tranquil island chain evacuated.

In the Bahamas, the government urged tourists to evacuate the sparsely populated southeastern islands and the Royal Bahamas Defence Force dispatched marines to bring food and water to the eastern islands of Mayaguana and San Salvador.

Turks and Caicos, a British territory, was pummeled for four days by Hurricane Hanna earlier this week. It caused widespread flooding and some damage, but did far worse when it drifted toward Haiti as a tropical storm, creating floods that had killed 163 people by Saturday.

Dennis Freeburg, who lives in Providenciales, managed to get a flight out to Florida, but he plans to return to the island chain, which he says is a paradise for scuba divers like him.

"This is just ... the bad part of living down in the Caribbean, you've got to deal with the storms," the 46-year-old said as he waited to board a flight to Miami with his miniature dachshund, Rue.

___Associated Press writer Mike Melia contributed from Nassau, Bahamas.