According to the United Nations Children's Fund, more than 18.5 million children in Nigeria lack access to school, with females accounting for more than half of the total.

This represents a stunning increase in the number of out-of-school children in Africa's most populous country, which UNICEF estimated to be 10.5 million last year.

Rahama Farah, the head of UNICEF's office in the northern city of Kano, told reporters on Wednesday that 60% of the children out of schools are girls.

"In Nigeria there are 18.5 million out-of-school children, 60 percent of these... are girls," he said.

He said that attacks on schools in the north by jihadists and criminal groups kidnapping for ransom had led to the rise.

Since the kidnapping of more than 200 schoolgirls from the northeastern town of Chibok by Boko Haram extremists in 2014, dozens of other schools have been targeted in similar mass abductions. According to UNICEF, gunmen abducted over 1,500 pupils last year, killing 16 of them.

The majority of the child captives were released following discussions, while several remain imprisoned in jungle hideouts.

According to UNICEF, almost 11,000 schools in Nigeria were closed due to insecurity since December 2020. Parents, however, are afraid to take their children to school in those that are still open, according to Farah.

"These attacks have created an insecure learning environment, discouraged parents and caregivers from sending their children to schools," he said.

Following the closure of schools in northern Nigeria, UNICEF has issued a warning about an increase in reported cases of underage marriages and early pregnancies.

Farah elaborated that even before the mass abductions, barely one in four girls from "poor, rural families" finished junior high school in the mostly Muslim north.

Now, he claims, the insecurity "heightens gender inequity."