“I am Abubakar Shekau and our brothers are behind the kidnapping in Katsina,” the man on the recording said. Shekau is the leader of one of the Boko Haram factions.
CNN was unable to independently verify the authenticity of the message.
The message claimed that Boko Haram had been targeted at the school because of the group’s long-standing goal of stopping “Western” education in northern Nigeria, but a government official told CNN on Monday that the kidnappers had been in contact with a school teacher, raising the prospect of a rescue negotiation.
There have been several estimates of the number of children abducted from the school. Government officials said it was difficult to keep an accurate track of the figures as some children fled during the attack and others had escaped and returned to villages and school over the weekend.
“Schools should be a place of safety and learning, but for these boys and their families it has become a nightmare,” Shannon Ward, country director of Save the Children in Nigeria, said in a statement on Monday. . “This could have a profound impact on children, not just the boys who were taken prisoner, but also those who had to flee and hide from armed violence or those who saw what happened.”
The kidnapping is outside the usual area of Boko Haram activity. Its operations have generally focused on the northeast of the country, although security analysts believe its scope has changed, following a security crackdown in the region.
In recent years there have been several kidnappings for rescue in Katsina State, but not on this scale.
Several witnesses told CNN that those who attacked the school were gunmen from Fulani, an ethnic group that has been involved in kidnappings and criminal activities in the area.
Boko Haram’s Shekau faction was behind the kidnapping of nearly 300 schoolgirls in Chibok in 2014. Their captivity lasted for years and many of the children were never returned after a negotiated release.
In 2018, a Boko Haram separatist faction known as ISWAP kidnapped more than 100 girls in Dapchi. All but one were released weeks later, after negotiations.
While these are the most prominent examples, Boko Haram has abducted more than 1,000 children since 2013, according to UNICEF.
The United Nations strongly condemned the abductions on Sunday and called for the “immediate and unconditional release” of the children.