US defence officials say they are opening an investigation into allegations of child sex abuse by Afghan security forces and reports that US personnel deliberately overlooked it.
The probe by the Pentagon's inspector-general comes after The New York Times last month reported that US troops in Afghanistan had been instructed by their superiors to overlook cases of Afghan police or commanders sexually abusing teenage boys, even if it took place on military bases.
The practice is known as "bacha bazi," which means "boy play" in local languages.
"Is there - or was there - any guidance, informal or otherwise, to discourage reporting by DoD (Department of Defense) affiliated personnel?" a memo from the inspector-general's office asks.
"What training on identifying and responding to alleged child sexual abuse ... has been conducted or planned?"
The memo, sent to leaders across the US military, also asks for information on the number of cases of child sex abuse alleged against Afghan government officials that were reported to US or coalition forces.
The Times based its report on accounts from multiple soldiers and the father of a marine who was killed in 2012.
The report said a former US special forces captain beat up an Afghan militia commander for keeping a boy chained to his bed as a sex slave, and afterward was stripped of his command and withdrawn from Afghanistan.
The Afghan Interior Ministry has rejected reports that it was not addressing the practice of bacha bazi, which it called a "heinous and indecent act" that is illegal under Afghan laws.
The Afghan government has in the past tried to crack down on the ancient and outlawed practice of child abuse, which is prevalent across rural parts of the country.