Updated

A new study says thousands of Bangladeshi children who live in the capital's slums are working an average of 64 hours a week.

The study, released Wednesday by the London-based Overseas Development Institute, says many of those children are employed in garment factories that make clothing for top global brands.

The study is based on a survey of 2,700 slum households in Dhaka. It found that 15 percent of children aged 6-14 were not attending school so they could work full time.

In Bangladesh, it is illegal for children under 14 to work.

Authorities did not immediately respond for requests for comment.

Bangladesh's garment industry, the world's second largest after China, provides an economic lifeline for the impoverished country, accounting for some $25 billion in annual exports.