The allegations were attributed by Amnesty International to systemic failures in accountability and justice during the Buhari administration.
Former President Muhammadu Buhari governed Nigeria from 2015 to 2023, a period that global human rights body, the Amnesty International says was marked by several grave human rights violations involving state security forces and other armed actors.
In a compilation released by the rights group on Monday, Amnesty International cited multiple incidents across the country, alleging unlawful killings, suppression of dissent, attacks on journalists, and abuses against vulnerable populations during Buhari’s eight years in office.
Buhari died in July 2025, aged 82.
Among the incidents highlighted was what Amnesty described as the "Mass slaughter of over 350 men, women and children by Nigerian military in Zaria between 12–14 Dec. 2015."
The organisation also accused Nigerian security agencies of targeting pro-Biafra activists, stating that "The Nigerian security forces carried out chilling campaign of extrajudicial executions and violence resulting in the deaths of at least 150 peaceful pro-Biafra protesters between August 2015 and August 2016."
Muhammadu Buhari ruled Nigeria from 2015–2023. Here are some of the gross human rights violations during his rule:
1. Mass slaughter of over 350 men, women and children by Nigerian military in Zaria between 12–14 Dec. 2015. pic.twitter.com/o8jmgtX8Nc
— Amnesty International Nigeria (@AmnestyNigeria) December 15, 2025
According to Amnesty International, one of the deadliest episodes occurred during the 2016 Biafra Remembrance Day. It said: "By far the largest number of pro-Biafra activists were killed on Biafra Remembrance Day on 30 May 2016 when an estimated 1,000 IPOB members and supporters gathered for a rally in Onitsha, Anambra State. The night before the rally, the security forces raided homes and a church where IPOB members were sleeping. Many were slaughtered, some burnt alive."
The group further linked rising communal violence to what it described as government inaction, noting that "The Buhari administration’s failure to bring perpetrators to justice fuelled a bloody escalation in the conflict between farmers and herders across the country, resulting in at least 3,641 deaths in three years. Over 57% of the 3,641 recorded deaths occurred in 2018."
Restrictions on press freedom were also cited. Amnesty stated that "Under Buhari, journalists were arrested, intimidated and harassed. Bloggers were beaten. At least 19 journalists and media practitioners were attacked, arrested, tortured, harassed and threatened between January and September 2019. At least, three journalists had to go into hiding. Daily Trust and Premium Times were raided by security forces."
On the nationwide protests against police brutality in 2020, the organisation said: "Peaceful #EndSARS protests seeking an end to the atrocities of SARS — a callous unit of the Nigeria Police, was met with violent crackdown. At least, 56 people were killed nationwide. At least, 12 protesters were killed at #LekkiTollGate and Alausa on 20 Oct. 2020."
Amnesty International also accused security forces and allied groups of abusing women and girls affected by the Boko Haram insurgency, alleging that "Thousands of women and girls who survived the brutal rule of the Boko Haram armed group were further abused by the Nigerian security forces and CJTF who claim to be rescuing them. The women and girls were raped, sometimes in exchange for food."
The allegations were attributed by Amnesty International to systemic failures in accountability and justice during the Buhari administration.
There have been concerns over what has been described as human rights abuses in the country, with repeated successive government promises to end the menace said to have failed to materialise.