There has been "nearly zero progress" in tackling the lack of access to school in many of the world's poorest countries, a UN agency has said. There had been little substantial progress in the past decade in ending the problem of children not having schools to attend.
There are still 123 million school-age children without schools, Unicef said, despite targets by world leaders. Unicef said efforts to increase the participation rate in school had "stagnated".
The UN's children's agency blamed "pervasive levels of poverty", conflict and humanitarian emergencies.
International pledges to create school places were not addressing "the realities of a volatile world", head of education Jo Bourne said. "This business-as-usual approach will not get the most vulnerable children into school - and help them reach their full potential - if they continue to be trapped in poverty, deprivation and insecurity," she said. Ms Bourne said that making more rapid progress on getting children into school would depend on tackling the underlying problems - such as ending conflicts that made school unsafe.
The problem is most acute in sub-Saharan Africa, where the lack of school places has been exacerbated by an increasing population. Those most likely to miss out are the poorest families from the poorest countries.
Conflicts in Syria and across the Middle East have reversed improvements in education levels in the region, with an additional 3.4 million children out of school. About a fifth of children in the world without access to school are living in conflict zones. They might be refugees whose education has been interrupted or living in areas where it is too dangerous to go to school or where school buildings have been destroyed.
The target for universal primary education was missed in 2015. And another UN agency, Unesco, warned that the latest targets, the sustainable development goals, were already likely to be missed. The international goals promise universal primary education for 2030, but Unesco said that on current trends this would not be achieved until 2042. Another 69 million teachers would need to be recruited to deliver international education promises for 2030.
There were also shortfalls in funding from international donors. Unicef said that up to June 2017, it had received only 12% of the funding needed to educate children in areas affected by a humanitarian crisis.