Nigerian security forces failed to act on an advance warning about a raid by the Islamist militant group Boko Haram on a school that led to the abduction of more than 200 girls last month, Amnesty International said.
Nigeria's military headquarters in the Borno state capital, Maiduguri, became aware of the imminent attack by Boko Haram on the northeastern town of Chibok at just after 7pm on April 14, Amnesty said yesterday in a statement, citing "credible sources" it interviewed. By midnight, the attack was under way.
The abduction, which came on the same day as the worst-ever bomb attack on the capital, Abuja, has sparked international protests and criticism of President Goodluck Jonathan's response.
"The fact that Nigerian security forces knew about Boko Haram's impending raid, but failed to take the immediate action needed to stop it, will only amplify the national and international outcry at this horrific crime," Netsanet Belay, Amnesty's Africa director for research and advocacy, said in the statement.
Boko Haram leader Abubakar Shekau has claimed responsibility for the abduction of 276 girls from their dormitories in Chibok.
His threat to sell the girls in "markets" and marry them off has galvanised a global campaign to free them joined by US first lady Michelle Obama and Pakistani activist Malala Yousafzai.
British and US teams arrived in Abuja yesterday to help Nigerian authorities search for the girls.
The kidnapping, along with two bombings in Abuja in the past month and regular outbreaks of deadly violence in the northeast, has plunged Jonathan's government into a credibility crisis among Nigerians.
"It amounts to a gross dereliction of Nigeria's duty to protect civilians, who remain sitting ducks for such attacks," Belay said in the statement.
"The Nigerian leadership must now use all lawful means at their disposal to secure the girls' safe release."
In Nigeria there have been protest marches in major cities, including Abuja, the commercial capital Lagos and the southern oil hub of Port Harcourt, urging the government and the security forces to do more to rescue the girls.
The conflict between Boko Haram and the Nigerian military has killed at least 2,000 people this year, Amnesty said yesterday.