Nigeria's President-elect Muhammadu Buhari says he cannot promise that authorities will find the 219 schoolgirls kidnapped a year ago by Boko Haram militants in the northeastern village of Chibok.
"We do not know if the Chibok girls can be rescued,'' he said in a statement Tuesday as the country was marking the one year anniversary of the mass abduction.
Buhari has criticized the current government's efforts to find the girls, saying his administration "will act differently from the government we replace." He said on the day he takes office, Boko Haram militants will know the "strength of our collective will."
Amnesty International said the militants have abducted at least 2,000 women in Nigeria since the start of 2014 and forced many of them into sexual slavery and armed combat.
The Amnesty report issued Tuesday describes Boko Haram's treatment of the women and men who come under its power when the group takes over a village or town. The report, based on accounts from nearly 200 witnesses, documents the killing of more than 5,000 civilians in northeast Nigeria from early 2014 through the present.
Amnesty says men and boys are regularly conscripted or executed, and women and girls are kidnapped, forced to marry Boko Haram fighters, sexually assaulted, and in many cases taught to fight alongside the militants.
One witness describes being forced to participate in an attack on her own town. She said she was also raped repeatedly. The witness also described the stoning of kidnap victims who refused to fight alongside Boko Haram.
Buhari won recent elections in Nigeria in part by promising to do more to fight the Islamist militants.
The United Nations Children Fund said Monday that 800,000 children have been displaced by Boko Haram violence, nearly half the 1.5 million people uprooted by the militants' campaign.
In Abuja, protesters held a silent vigil Monday after one year of campaigns to "Bring Back Our Girls."
Boko Haram has carried out a campaign of terrorism since 2009 to turn Nigeria into an Islamic state, and has recently spread across the borders to attack towns in neighboring Cameroon, Chad and Niger.