At least 2000 women have been abducted by Boko Haram, detained in prisons and houses and subjected to forced marriage, stonings and sexual slavery, according to a report that berates Nigeria's "dismal" security situation.
The Amnesty International report - based on more than 150 witness accounts - charges the Islamic militants with the deaths of more than 5500 civilians and paints the most detailed picture yet of the oppression inflicted upon young women.
The Islamic militant group should be brought to justice over war crimes such as "rapes, sexual slavery and other forms of sexual violence", according to the Amnesty study, published today - a year after the group abducted 276 schoolgirls from a secondary school in Chibok.
Soon after taking control of a town, militants implemented restrictions of movement, particularly on women, the report says. Failure to attend daily prayers was punishable by public flogging.
"Although rape was banned in territories under Boko Haram control, women and girls were also raped in secret outside forced marriages," the report says. "Abducted men and boys were forced to provide services for Boko Haram or to join them as fighters."