A sailboat passing through the southern Bahamas islands with about 150 Haitian migrants on board capsized after running aground, killing up to 30 people and leaving the rest clinging to the vessel for hours, authorities have said.

The exact death toll remained uncertain on Tuesday morning.

Authorities on the scene confirmed at least 20 dead and determined the number could reach 30 based on accounts from survivors, said Lieutenant Origin Deleveaux, a Royal Bahamas Defence Force spokesman.

The remains of five victims had been recovered and the Bahamas military and police were working with the US Coastguard to recover additional bodies as they pulled survivors from the stranded sailboat.

"Right now, we are just trying to recover as many bodies as we possibly can," Deleveaux said.

Authorities believe the migrants had been at sea for eight to nine days with limited food and water and no life jackets, Coastguard Lieutenant Commander Gabe Somma said.

Many were severely dehydrated when the first rescue crews reached them.

The boat, in addition to being overloaded, likely encountered rough weather, Deleveaux said.

This latest incident occurred late Monday near Harvey Cays, about 125 kilometres southeast of New Providence, the island that includes the capital of Nassau, 417 kilometres southeast of Miami.

Fishermen spotted the dangerously overloaded boat and alerted the Bahamas military, which asked the Coastguard for assistance in locating the vessel, Somma said.

Clinging to the ship

By the time it was spotted, the 40-foot boat had run aground in an area dotted with tiny outcroppings and reefs and then capsized.

Photos taken by the Coastguard showed people clinging to every available space on the overturned vessel.

Some were taken to a clinic on nearby Staniel Cay for treatment for dehydration.

By late Tuesday afternoon, the Coastguard and Bahamian authorities had rescued about 110 people, including 19 women.

Deleveaux said there were no children on board.

Source: AP