Nearly half all children in Afghanistan are out of school due to conflict, poverty, child marriage and discrimination against girls, the number rising for the first time since 2002, humanitarian organisations said in a report on Sunday.
The number of children deprived of schooling is at its highest rate since 2002 -- the year after the US-led ouster of the repressive Taliban regime, which had banned girls from the classroom.
Girls remain more likely to miss out on a formal education, making up 60 percent of the 3.7 million children aged between seven and 17 not at school.
Spreading violence has forced many schools to close, undermining fragile gains in education for girls in a country where millions have never set foot in a class room.
Some 3.7 million children between the ages of seven and 17, or 44 percent, are out of school, 2.7 million of them girls, Education Minister Mirwais Balkhi told a seminar, explaining a study conducted by UNICEF, USAID and the independent Samuel Hall think-tank.
The Taliban, seeking to oust the U.S.-backed government and return the country to strict Islamic rule after their 2001 ouster, are adamantly opposed to education for girls and threats from Islamic State have forced the closure of dozens of schools.
Child marriages and a shortage of female teachers were additional factors keeping girls away from the classroom.
The report by United Nations Children's Fund (UNICEF) also estimated that up to 300,000 children are at risk of dropping out before the end of the year.
Those children most at risk often live in rural areas and face displacement, insecurity and a lack of schooling facilities.
Without mentioning the Taliban or Islamic State, Balkhi said there were "many reasons" for children not going to school.
"Education of children is the most important development in all human communities," he said. "It is the most important tool in fighting war, poverty and unemployment."
In April this year, militants set ablaze two schools and widespread violence had led to closure of hundreds of private schools.
"Business as usual is not an option for Afghanistan if we are to fulfil the right to education for every child," said Adele Khodr of UNICEF in the report.
"When children are not in school, they are at increased danger of abuse, exploitation and recruitment."