Hurricane Ike over Gulf of Mexico, aims at Texas

* Hurricane Ike strengthens as it heads to Gulf of Mexico

* Ike seen hitting Texas, west of main Gulf oil fields

* Florida keys may face heavy swells, rip currents

* More heavy rain may cause flash floods in western Cuba

By Jeff Franks

HAVANA, Sept 10 (Reuters) - Hurricane Ike swirled over the Gulf of Mexico on Wednesday, targeting Texas near the U.S. offshore oil patch after toppling decrepit buildings in Cuba's capital and ripping the communist-run island from end to end.

Ike, a Category 1 storm with 85 mile-per-hour (140 kph) winds, left a long trail of destruction across the Caribbean and had energy companies fearful it could do the same to their Gulf oil rigs as they scurried to evacuate workers and shut down production.

Forecasters said Ike would likely regain power in the Gulf's warm waters and become a major storm again, revving up to a Category 3 on the five-step hurricane intensity scale with a minimum of 115 mph (178 kph) winds.

But latest projections pointed Ike toward the middle of the Texas coast, skirting to the west of the main region for offshore production in the Gulf, which provides a quarter of U.S. oil and 15 percent of its natural gas.

Oil futures had earlier dipped more than $2 to below $105 on the forecast, although the U.S. National Hurricane Center in Miami warned that its projections were subject to change.

New Orleans, still scarred by Katrina, which killed 1,500 people and caused $80 billion in damage on the U.S. Gulf Coast in 2005, appeared to be out of danger.

At 5 a.m. EDT (0900 GMT), the hurricane center said in its latest advisory Ike was 125 miles (200 km) north-northeast of the western tip of Cuba and about 465 miles (750 km) southeast of the mouth of the Mississippi River. It was churning west-northwest at 8 mph (13 kph), and was expected to continue on that path for the next day or two.

Rainfall of up to three inches (7.6 cm) was possible in the lower Florida keys, which could also face storm surges, large waves and isolated tornadoes and waterspouts on Wednesday, the center said. Southwest Florida was expected to see up to four 4 inches (10 cm) of rain.

In Cuba, big waves and storm surges were expected to subside on Wednesday, but heavy rains on the western end of the island could produce flash floods, the center said.

Ike has already caused widespread damage in Cuba.

Few official figures have emerged, but state-run media showed a panorama of destruction across the island, still reeling from the more powerful Hurricane Gustav 10 days ago.

Ike struck eastern Cuba on Sunday with 120 mph (195 kph) winds and torrential rains that destroyed buildings, wiped out the electricity grid, toppled trees, leveled crops including sugar cane fields, and turned rivers into roaring torrents.

COSTLY CUBAN CLEANUP

After up to 15 inches (40 cm) of rain fell on the island the downpour continued on Wednesday even as Ike moved away, causing widespread flooding and growing alarm among officials.

Ike's damage could total between $3 billion and $4 billion, according to some official sources, said Elisabeth Byrs of the U.N. Office for the Coordination of Humanitarian Affairs at a news briefing in Geneva.

Cuba said Ike did no serious damage to its key nickel mines and processing plants and it expected to restart production of its top export in a few days.

Havana, which barely escaped the full wrath of Gustav, was pounded by Ike's winds and rain on Monday and Tuesday, which toppled at least 16 of the many beautiful but crumbling old buildings in the capital.

"It sounds like Havana has been invaded by an army of ghosts," Havana resident Maria Valdez said, referring to the howling winds that blew through streets littered with fallen trees, foliage and debris.

A total of 2.6 million people were evacuated ahead of Ike, or about 22 percent of the country's 11.4 million population, but officials said four people died in the eastern provinces.

No deaths were reported from Gustav, but state-run Prensa Latina said on Tuesday it damaged 140,000 buildings -- 90,000 of them homes -- when it blasted across the Isle of Youth and westernmost province of Pinar del Rio.

After crossing the eastern provinces, Ike dipped into the Caribbean and headed northwest where it made its second Cuba landfall on Tuesday at Punta la Capitana in westernmost Pinar del Rio province.

The storm ripped across the same region struck by Gustav before leaving the island near the town of Manuel Sanguily on Pinar del Rio's north central coast.

Before Cuba, Ike hit Britain's Turks and Caicos Islands and the southern Bahamas as a ferocious Category 4 hurricane. Floods triggered by its torrential rains were blamed for at least 71 deaths in Haiti, where Tropical Storm Hanna killed 500 last week.

The United Nations said it would launch an emergency appeal for money with about 800,000 people in Haiti in need of urgent help, nearly half of them children. The impoverished country has been hit by four storms in a month. (Additional reporting by Esteban Israel, Marc Frank, Rosa Tania Valdes and Nelson Acosta in Havana, Stephanie Nebehay in Geneva, Jim Loney in Miami; Editing by Tom Brown and Eric Walsh)