Fifteen people are dead and nearly 70 are missing after a boat carrying up to 200 Haitian migrants capsized off the Caribbean islands of Turks and Caicos.
Emergency services managed to rescue 113 people and some of the injured were taken to hospital after the incident, thought to have happened on Sunday.
The US Coast Guard has been leading the search for survivors among the reefs.
Haitians often travel through the islands in overcrowded boats, hoping to find work in the Bahamas or Florida.
The flimsy boat had been at sea for three days when it accidentally steered into a reef as it tried to avoid being spotted by a police patrol vessel, one survivor, Alces Julien, told the Associated Press news agency from hospital.
Lt Cdr Matthew Moorlag of the US Coast Guard told the BBC his team had rescued 113 people.
It was helping local authorities in the search for those still missing, he added.
"Unfortunately many people lose their lives trying to reach the United States illegally, anywhere of 100 or more per year," he said, adding that the heavy loss of life was mostly due to overcrowding of vessels.
"They don't have enough life-saving gear or signalling gear to ensure that they are able to survive if they do have any problems at sea," he said.
At least nine people, including a pregnant woman, died in May this year when a boat carrying nearly 30 people, mostly Haitians, sank off the Florida coast.
In May 2007, at least 61 Haitian migrants died when a boat carrying 150 people sank off the Turks and Caicos, a British territory.
Some of the survivors said the boat had been rammed by a patrol boat from the Turks and Caicos, then towed out to sea.