Untold stories of young Nigerian women kidnapped by Boko Haram highlight a documentary debuting on Monday that reveals diaries kept by survivors forbidden from talking about their captivity.

The diaries, secretly given to the U.S.-based documentary producers by former captives, detail life under the jihadi group that, according to the United Nations, has abducted more than 1,000 children in the last five years in northeast Nigeria.

Appearing in the film "Stolen Daughters: Kidnapped by Boko Haram" are survivors from the town of Chibok, where the 2014 abduction of about 220 schoolgirls sparked global outrage, and girls kidnapped elsewhere in Nigeria who escaped the militants.