MIAMI - TROPICAL Storm Hanna closed in on the southeastern US coast on Friday after leaving 136 dead in Haiti as a powerful hurricane swept across the Atlantic, posing a potential threat to Caribbean islands and the United States.

Hanna pushed through the Bahamas on its way to the US Atlantic coast, prompting emergency preparations before its expected arrival late Friday after having caused flooding and landslides in Haiti that left thousands homeless.

Hanna could strengthen and gain hurricane status on Friday before reaching the US near North or South Carolina at the weekend, the Miami-based National Hurricane Center (NHC) said.

Hanna 'has been an erratic storm. It's already done a lot of flooding (and) we are expecting it to strengthen slightly' before Friday, NHC forecaster John Cangialosi said.

Heavy rain, wind and high surf were forecast along the southeastern coastline ahead of the storm's arrival as governors in North Carolina and Virginia declared states of emergency while South Carolina Governor Mark Sanford called for voluntary evacuations in two counties threatened by the storm.

At 0600 GMT on Friday, the center of the storm was 90 kilometres north of Great Abaco Island in the Bahamas and about 790 kilometres south of Wilmington, North Carolina, the NHC said.

The storm was moving toward the northwest at about 30 kilometres per hour and was expected to pick up speed as it clears the Bahamas and heads northwest to the US coast.

'The center of Hanna will be near the southeast coast of the United States later today,' it said.

Hanna packed sustained winds of near 100 kilometres per hour, with higher gusts, according to reports from a reconnaissance aircraft.

The storm was rolling toward the northwest at about 30 kilometres per hour and was expected to steadily pick up speed on Friday as it heads from the Bahamas north to the US coastline.

A hurricane watch remained in effect for parts of the North and South Carolina coast as authorities prepared for possible flooding and kept a wary eye on a more formidable storm out in the Atlantic.

Hurricane Ike remained an 'extremely dangerous' Category Four storm on the five-level Saffir-Simpson scale as it moved over the western Atlantic, with maximum sustained winds of near 215 kilometres an hour.

At 0300 GMT on Friday, the center of Ike was about 760 kilometres north-northeast of the Leeward Islands and was moving west at 22 kilometres an hour, according to the NHC, which advised authorities in the Bahamas and the Turks and Caicos Islands to keep a close watch on the formidable storm.

Cangialosi described it as 'absolutely a powerful hurricane', adding that 'there is no immediate threat' to land. He said it was too soon to tell if it would track north toward the US eastern coastline, or westward toward the Gulf of Mexico.

On its current forecast path the outer bands of Ike would also graze the northern portion of the island of Hispaniola - the Caribbean island shared by Haiti and the Dominican Republic - on Saturday.

A third system, Tropical Storm Josephine, was reported in the eastern Atlantic some 1,010 kilometres west of the southernmost islands of Cape Verde, moving in a west-northwest direction at around 17 kilometres an hour.

The storm, which disrupted shipping in the area but was not close to land, had maximum sustained winds of 75 kilometres per hour, with higher gusts.

The storms follow Hurricane Gustav, which ripped through the Caribbean then slammed the US Gulf Coast, and Tropical Storm Fay, which also pounded several Caribbean islands and made landfall in Florida four times, dumping record amounts of rain.

On Thursday, Haiti's third largest city Gonaives remained under water in the wake of Hanna as Alta Jean-Baptiste, head of Haiti's civil protection office, said the toll had risen to 136, mostly in the Gonaives area.

She also said that flooding and landslides triggered by the heavy rain forced nearly 10,000 people into shelters - not including thousands more who had evacuated Gonaives, a city of 300,000.

Senator Yuri Latortue, who represents the city, called the situation 'catastrophic,' saying some 200,000 people there had not eaten for three days.

Hanna struck Haiti one week after it was hit by Hurricane Gustav, which killed 77 people. Two weeks ago, Tropical Storm Fay sparked flooding in the country that left about 40 people dead. -- AFP