The children, aged between 12 and 18, were lured from their home villages by brokers and sold on, said Lokman Hakim, who led the rescue operation.

“We rescued 46 of them in the last two days. These boys were used as slaves with no salaries, no rights and no way to escape,” he told AFP.

Authorities launched a crackdown in 2006 to rescue hundreds of children sold into bonded labor on fish processing farms in Bangladesh's remote south.

Although child labor is banned in Bangladesh, charities and rights groups have said millions of children are still employed on brickfields, on farms, as domestic help and in the construction industry.