The AFP story detailed how Taliban insurgents are using enslaved children to mount crippling insider attacks against police positions

AFP's Kabul bureau has won one of Asia's most prestigious journalism prizes for a report exposing the practice of "bacha bazi", or institutionalised child sex slavery, and its detrimental effects on security in war-torn Afghanistan.

Bureau chief Anuj Chopra and the team of journalists, photographers and video reporters won the Society of Publishers in Asia (SOPA) award for "Excellence in Human Rights Reporting" for their exclusive on how the Taliban exploit bacha bazi to infiltrate security ranks.

The award was announced at a ceremony in Hong Kong Thursday, with the judges commending "impressive investigative work in one of the world's most difficult reporting regions, bringing to light some truly horrifying abuses."

Other winners in the evening included the Washington Post for a series on violence and injustice against women in India, and the Financial Times, which took the Feature Writing category for a report on neo-Maoism in China.

AFP Kabul also won the "English Feature News" category at the Human Rights Press Awards in Hong Kong last month for its work on the bacha bazi issue.

"AFP is delighted at the recognition of the fine work of our Kabul bureau which, like the rest of the media in the country, operates in extremely difficult conditions," said AFP regional director for the Asia-Pacific region Philippe Massonnet.

"This series would not have been possible without the courage of victims, their families, and officials who spoke with us and shared their stories," he added.

The ancient custom of bacha bazi, one of Afghanistan's worst human rights violations, sees young boys -- sometimes dressed as women -- recruited to police outposts for sexual companionship and to bear arms.

The AFP story detailed how Taliban insurgents are using these children to mount crippling insider attacks that have killed hundreds of police in southern Afghanistan over the previous two years.

Afghanistan's president Ashraf Ghani ordered an investigation into the abuse last year in the wake of a flurry of international reaction to the report, though the results have not yet been announced.

The practice has seen a chilling resurgence in post-Taliban Afghanistan, but officials have told AFP they were reluctant to take action, fearing that angry policemen would abandon their posts and pave the way for the Taliban.

The bureau followed up the initial story, which was published in June last year, with a series on the impact of the pervasive abuse, long shrouded in silence, including the hopeless fight to save kidnapped children.

They plan to further develop the story by chronicling the lives of bacha bazi survivors and their struggle to cope with the trauma in a country at war with little support for victims.