Rescuers carried out search operations off the northern coast of Mozambique on Monday after a makeshift ferry boat capsized, killing at least 97.

The converted fishing boat, with about 130 people on board, ran into trouble late on Sunday as it was headed for an island off Nampula province, officials said.

On Sunday, authorities said the boat was believed to have sunk because it was overcrowded and unsuited to carrying passengers. It was later clarified that the vessel capsized after taking on water.

"Water filled the boat ... and the tragedy happened," Menque Amade, a crew member who survived the accident, told national broadcaster TVM.

Silverio Nauaito, the island's administrator, told AFP that six bodies were pulled from the waters on Monday, bringing the death toll to 97.

Rescuers have found 12 survivors, and search operations are continuing, the official said.