Ike was moving west-northwest but was expected to take a turn to the west on Thursday night and Friday, taking it over the open waters of the west-central Atlantic.

It was still too early to tell what if any land areas might be affected by Ike, or whether it would threaten the oilfields in the Gulf of Mexico, the Miami-based center said.

Hanna's torrential rains had already submerged parts of Haiti, stranding residents on rooftops and prompting President Rene Preval to warn of an 'extraordinary catastrophe' to rival a storm that killed more than 3,000 people in the flood-prone Caribbean country four years ago.

Hanna was forecast to move over the central and northern Bahamas on Thursday, strengthening back into a hurricane before hitting the US coast near the North Carolina-Virginia border on Saturday.

Ike had top sustained winds of 130kmh as it swept across the open Atlantic 1,080km east-northeast of the Leeward Islands.

The US National Hurricane Center said Ike could strengthen into a 'major' Category 3 hurricane with winds of 178kmh to 209kmh as it reaches the southern Bahamas and nears Cuba early next week.

Major hurricanes are those that are ranked from Category 3 to Category 5 on the five-step Saffir-Simpson intensity scale.

Tropical Storm Josephine also marched across the Atlantic on a westward course behind Ike but it had begun to weaken.

The burst of storm activity follows Hurricane Gustav, which slammed into Louisiana near New Orleans on Monday after a course that also took it through Haiti, where it killed more than 75 people.

The storms were troubling news for US oil and natural gas producers in the Gulf of Mexico and for the millions of people living in the Caribbean and on America's coasts.

The US government has forecast 14 to 18 tropical storms will form during the six-month season that began on June 1, more than the historical average of 10. Josephine was already the 10th, forming before the statistical peak of the season on Sept 10.

The record-busting 2005 season, which included deadly Hurricane Katrina, had 28 storms.

'Really catastrophic
In Haiti, officials were still counting the scores of people killed by Gustav when Hanna struck the impoverished nation on Monday night.

Authorities said Hanna caused flooding and mudslides that killed at least 61 people across Haiti, including 22 in the low-lying port of Gonaives. The death toll was expected to rise as floodwaters receded and rescuers reached remote areas.

'We are in a really catastrophic situation,' said Mr Preval, who planned to hold emergency talks with representatives of international donor countries to appeal for aid.

'It is believed that compared to Jeanne, Hanna could cause even more damage,' he said, referring to a storm that sent floodwaters and mud cascading into Gonaives and other parts of Haiti's north and northwest in September 2004, killing more than 3,000 people.

Gonaives residents were still stranded on their rooftops two days after the floodwaters rose and the government did not know the fate of those who had been in hospitals and prisons.

'There are a lot of people on rooftops and there are prisoners that we cannot guard,' Mr Preval said.

Hanna had hovered off Haiti's coast since Monday, drowning crops in a desperately poor nation already struggling with food shortages. It also triggered widespread flooding in the neighboring Dominican Republic.

The Miami-based hurricane center said Hanna had begun moving northward with top winds of 95kmh. It was forecast to turn northwest across the central and northern Bahamas in the next two days and then hit the US coast in North Carolina or the mid-Atlantic states on Saturday.

It was too early to say where Ike might go, after it churns through the Caribbean, but the storm has drawn the attention of energy companies running the 4,000 offshore platforms in the Gulf of Mexico that provide the United States with a quarter of its crude oil and 15 per cent of its natural gas.

By late Wednesday, Josephine was swirling over the far eastern Atlantic about 605km west of the Cape Verde Islands. It was moving west but had begun to weaken, with top sustained winds dropping to 95kmh. -- REUTERS