More than 50 people were missing after a boat — possibly being ferried by human traffickers — sank Sunday off a southern Bangladesh island bordering Myanmar waters, a police official said.

The wooden fishing boat went down near Saint Martin's island, about 75 miles south of the coastal resort town of Cox's Bazar, said local police chief Banaj Kumar Majumdar.

Survivors said the boat was carrying more than 100 people, police officer Mohammad Jasimuddin said.

Only three bodies had been recovered. About 50 people were still unaccounted for, based on statements from their relatives who have gathered on the shore. About 50 others either swam ashore or were rescued by local fishing boats, Jasimuddin said.

The passengers' nationalities were not immediately known, but Majumdar said they could be Bangladeshis or Myanmar refugees from camps at Cox's Bazar.

Police suspect human traffickers had been using the boat to try taking the passengers to either Thailand or Malaysia, Majumdar said.

Several thousand Myanmar refugees, mostly Muslims known as Rohingyas, have fled to Bangladesh over the years, claiming persecution by Myanmar's military junta and economic hardships.

In the last three months, police and the coast guard have arrested about 500 people — Bangladeshis and Myanmar refugees — in the same waters, mainly on trafficking or illegal entry charges.

Such accidents are common in Bangladesh, a delta nation with about 250 rivers. They are often blamed on poor navigation, unfit vessels and lax enforcement of safety regulations.