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 said Tuesday.

The exact death toll remained uncertain. Authorities on the scene confirmed at least 20 dead and determined the number could reach 30 based on accounts from survivors, said Lt. Origin Deleveaux, a Royal Bahamas Defense Force spokesman.

The remains of five victims had been recovered and the Bahamas military and police were working with the U.S. Coast Guard 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, Coast Guard Lt. Cmdr. 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.

“It was obviously just grossly overloaded, unbalanced, unseaworthy,” Somma said. “An incredibly dangerous voyage.”

The capsizing of overloaded vessels occurs with disturbing frequency in the area, most recently in mid-October when four Haitian women died off Miami. There have also been fatal incidents near the Turks and Caicos Islands, between Haiti and the Bahamas, and in the rough Mona Passage that divides the Dominican Republic and Puerto Rico.

“Unfortunately we see these types of tragedies occur on a monthly basis,” Coast Guard Chief Petty Officer Ryan Doss said. “Every year we see hundreds of migrants needlessly lose their lives at sea taking part in these dangerous and illegal voyages.”

It's common enough that the Coast Guard recently developed a public service announcement that will run on TV and radio in Florida, Haiti, the Bahamas and the Dominican Republic urging people not to risk the deadly ocean voyages.

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

Fishermen spotted the dangerously overloaded sailboat and alerted the Bahamas military, which asked the Coast Guard for assistance in locating the vessel, Somma said. 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 Coast Guard 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 Coast Guard and Bahamian authorities had rescued about 110 people, including 19 women. Deleveaux said there were no children on board. Smugglers will often seek to blend in with the migrants when they are captured and authorities did not announce any arrests.

Migrants have long traversed the Bahamian archipelago to reach the United States. Thousands have also settled in the Bahamas in recent years. Deleveaux said those rescued from the boat near Harvey Cays would be taken to a military base on New Providence, processed and then repatriated to Haiti. (AP)