At least 15 Haitian migrants have drowned and at least 65 more are missing after their boat capsized off the Turks and Caicos islands, local police and the US coast guard have said.

The authorities rescued 122 people from reefs southeast of West Caicos island after the boat sank late on Monday, Sergeant Calvin Chase, a spokesman for Turks and Caicos police, said.

"The boat ran aground on a reef, Molasses Reef, off West Caicos ... We have a total of 15 dead bodies now," he said.

Estimates on the number of people on board the stricken vessel range from between 160 and 200, the US coast guard has said.

Rescue effort

Barry Bena, a US coast guard spokesman, told Al Jazeera that all available resources were being used in the rescue effort.

Rescued migrants were being taken to the Turks and Caicos islands

"In this current situation anyone who has been rescued so far is being brought into the Turks and Caicos and that is probably what will continue with this case.

"Once they are brought in, they are not in our custody any more; we turn them over to the Turks and Caicos officials and they make a determination [on what to do with them] ... Our primary mission is to find as many survivors as we can."

Some of the most severely injured survivors were taken by helicopter for medical treatment to Providenciales, the capital of the Turks and Caicos.

The Turks and Caicos islands are a British territory in the Atlantic ocean, between the southern Bahamas and the north coast of Haiti.

Haitians often leave their country in crowded boats in an attempt to escape poverty and find work in the Bahamas or Florida.

Last week, the US coast guard found 124 Haitian migrants travelling on what they said was a "grossly overloaded" boat about 240 km southwest of the site of Monday's accident.

Those migrants were repatriated to Haiti on Monday.