Karl Merton Ferron, Associated Press
Vicky and Kevin Allen get hit by a wave in Ocean City, Md., as Tropical Storm Hanna enters the mid-Atlantic region Saturday.

KEY WEST, Fla. — "Extremely dangerous" Hurricane Ike grew to fierce Category 4 strength Saturday as it roared on an uncertain path that forced millions from the Caribbean to Florida, and Louisiana to Mexico, to nervously wonder where it would eventually strike.

Preparations stretched more than 1,000 miles as the massive, 135-mph storm took a southwesterly shift that could send it over Cuba and the Florida Keys by Tuesday before heading into the warm open waters of the Gulf of Mexico. And once again, a possible target was New Orleans and the already storm-weary U.S. Gulf Coast.

"These storms have a mind of their own," Florida Gov. Charlie Crist said after a meeting with mayors and emergency officials. "There are no rules, so what we have to do is be prepared, be smart, vigilant and alert."

First in Ike's path was the low-lying British territory of Turks and Caicos, already pummeled for four days this week by Tropical Storm Hanna. At the airport in Providenciales, Patrick Munroe had hoped to catch a departing flight, but was turned away, even before the airport shuttered.

"It looks really, really serious," he said. "And I think it's going to be devastating."

In Haiti, authorities tried to move thousands of people into shelters ahead of Ike, still struggling to recover from Tropical Storm Hanna. Rescue workers feared Hanna's death toll could rise into the hundreds in the flooded city of Gonaives and that aid efforts could be further impeded as Ike approached.

Hanna did not pack the same punch Saturday while racing up the U.S. Eastern seaboard, but it did cause one death in a traffic accident on Interstate 95 in Maryland. It also brought fits of wind and pelting rain all along its trek toward New England.

But Ike is another matter.

Tens of millions of people in countries spread over a swath of the hurricane zone monitored the trajectory of a storm that had a huge footprint, with tropical storm-force winds stretching up to 140 miles from its eye.

At 8 p.m. EDT, Ike's center was located about 60 miles east of Grand Turk Island as the storm moved west-southwest at about 15 mph, the National Hurricane Center in Miami said.

The center said Ike remained a Category 4 storm with sustained winds of about 135 mph and gusts even higher.

Center meteorologist Colin McAdie said the core of Ike was expected to pass "near or over" the Turks and Caicos soon and begin to affect the southeastern Bahamas overnight.

"It's a very dangerous storm," McAdie told The Associated Press from Miami. He added all indications were that Ike would remain a powerful storm.

"There's going to be some ups and downs, but we expect it to remain a major hurricane over the next couple days," he added.

In Louisiana, still recovering from last week's Hurricane Gustav, Gov. Bobby Jindal set up a task force to prepare for the possibility of more havoc.

"We're not hoping for another strike, another storm, but we're ready," he said.

Even as Gustav evacuees headed home, New Orleans Mayor Ray Nagin said officials were anxiously monitoring Ike's projected path toward the Gulf.

"Our citizens are weary and they're tired and they have spent a lot of money evacuating ... from Gustav," he said. He added that if Ike were to threaten, "my expectations this time is, it will be very difficult to move the kind of numbers out of this city that we moved during Gustav."

In Florida, batteries, water and gas cans became major commodities, as nearly the entire state appeared within the cone of areas that might be hit.

Jose Calbo planned to fly to Chicago later Saturday with his girlfriend, leaving his Miami-area home behind.

"Why be here without power and lights?" he asked. "There is nothing you can do. The best thing you can hope for is to board up the house, empty the freezer."

Visitors to the Florida Keys were under a mandatory evacuation order Saturday and a light but steady stream of traffic rolled out of Key West. In typical fashion, laid-back residents and business owners kept their shops, bars and restaurants open. But unique was the worry, still nearly four days ahead of potential landfall.

Jesse Damian hammered plywood over windows at The Bike Shop.

"The owners are usually like all the people who wait until the last minute around here," he said. "But this one's looking pretty bad."

Key West was last seriously affected by a hurricane in 2005, when Category 3 Wilma sped past. The town escaped widespread wind damage, but a storm surge flooded hundreds of homes and some businesses.