Boko Haram freed 13 hostages after authorities negotiated their release with the Islamist militants.
The kidnappings were part of a campaign of attacks last year by the jihadist group whose bid to create an Islamic state in the north-east has killed at least 20,000 people and forced some 2.7 million to flee since 2009.
Three hostages were lecturers from the University of Maiduguri, abducted while on an oil exploration trip in Magumeri, in Borno state, in July 2017. The other 10 were women police officers kidnapped in a raid on a convoy the previous month.
“Their release followed negotiations directed by President Muhammadu Buhari and facilitated by the International Committee of the Red Cross, ICRC,” a presidency spokesman said in a statement.
The ICRC acted as a neutral intermediary in the hostage release.
“The ICRC was not involved in any negotiations that led to the handover of the 13 people. The armed opposition handed the 13 people over to ICRC representatives who transported them to Nigerian authorities,” it said in a statement.
The ICRC was also an intermediary in the release in October 2016 and May 2017 of some of the more than 200 girls kidnapped by Boko Haram from Chibok in 2014.