Tropical Storm Hanna closed in on the southeastern United States after it hammered Haiti, triggering floods and landslides that killed at least 61 people and leaving thousands homeless, local authorities said.

Hanna could strengthen and gain hurricane status on Friday before reaching the US coastline, the Miami-based National Hurricane Centre 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, when it is due to pound the US states of North or South Carolina, Hurricane Centre forecaster John Cangialosi said.

At 1800 GMT (2am Singapore time) the centre of Hanna was about 330 kilometres east of Nassau in the Bahamas, moving toward the northwest at about 22 kilometres per hour.

Forecasters expected Hanna to turn north late Friday. On this path, 'Hanna will pass just east of the central and northwestern Bahamas (Thursday) ... and will be near the south-east coast of the United States by late Friday.'

The storm packed maximum sustained winds of near 100 kilometres an hour, with higher gusts.

Meanwhile monster Hurricane Ike turned into an 'extremely dangerous' Category Four storm on the five-level Saffir-Simpson scale as it moved over the western Atlantic Ocean.

At 1500 GMT Hurricane Ike churned in the Atlantic some 845 kilometres north-east of the Leeward islands, moving in a west-northwest direction at around 26 kilometres an hour. It packed winds of near 220 kilometres an hour, with higher gusts.

'It is too early to determine what land areas might be affected by Ike,' the Hurricane Centre said.

Mr 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 toward the US eastern coastline, or westward toward the Gulf of Mexico.

The margin of error in forecasting a storm's behavior rises considerably beyond the third day, said Hurricane Centre spokesman Dennis Feltgen.

Ike, however, 'will affect the Bahamas,' and forecasters 'expect it to remain a major hurricane,' Mr Feltgen said.

A third system, Tropical Storm Josephine, was reported in the eastern Atlantic some 840 kilometres west of the southmost Cape Verde Islands, moving in a west-northwest direction at around 17 kilometres an hour.

'Little change in strength is forecast during the next couple of days,' the Hurricane Centre said.

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.

Still, this is not an unusually busy storm season. 'We had five storms at one time in 1995 and 1971,' said Mr Feltman.

As meteorologists monitored Hanna and Ike, vast flooding in Haiti triggered by Hanna revived memories of lethal Tropical Storm Jeanne in September 2004, when about 3,000 people were killed, mostly in the northern city of Gonaives.

The UN peacekeeping mission in Haiti (MINUSTAH) on Wednesday carried out dramatic helicopter rescues to save those stranded by the high water.

Mountainous Haiti is especially prone to flooding and landslides due to widespread deforestation on its section of the island of Hispaniola, which it shares with the Dominican Republic.

Tens of thousands of people in both countries were forced to take refuge from driving rain and flooding, though there were no casualties reported in the Dominican Republic.

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 Haiti that left about 40 people dead. -- AFP