Despite efforts to improve girls' education in Afghanistan, just one in three currently attends school, UNICEF reports.
Just one in three girls are currently attending school in Afghanistan, marking the biggest drop in the number of school attendees since the Taliban were removed from power 16 years ago.
According to a report by UNICEF, some 3.7 million children between the ages of seven and 17, or 44 percent, are out of school, with girls accounting for 2.7 million of that figure, 60 percent.
"The ongoing conflict and worsening security situation across the country, combined with deeply ingrained poverty and discrimination against girls, have pushed the rate of out-of-school children up for the first time since 2002 levels," UNICEF's Afghanistan country study said in a statement.
The spread of violence had forced many schools to close, undermining fragile gains in education for girls in a country where millions have never set foot in a classroom.
The report added that up to 85 percent of girls were not going to school in some of the worst-affected provinces, such as Kandahar, Helmand, Wardak, Paktika, Zabul and Uruzgan.
Adele Khodr, UNICEF's Afghanistan representative, said those out of school were at an "increased danger of abuse, exploitation and recruitment [into armed gangs]."
She also emphasised the importance of school in giving children a point of orientation amid the disruptions caused by conflict.
"[Schooling] is about providing routine and stability in life, which is a wise investment given the insecurity across parts of the country," Khodr added.
Among others, the report also marked child marriage, shortage of female teachers and poor infrastructure as the main reasons further aggravating the situation.
'Year of Education'
Without mentioning the Taliban or the local chapter of the Islamic State of Iraq and the Levant (ISIL, also known as ISIS), Education Minister Mirwais Balkhi said there were "many reasons" for children not going to school.
The Taliban have waged a rebellion against the Western-backed Kabul government since being toppled from power in 2001 and has intensified attacks across the country in recent months, despite the cold winter months.
"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."
This comes as the Afghan government has declared 2018 as the "Year of Education".