Some children, abducted by extremist groups, are abused again by security forces when they are released. Others are indirectly harmed by fighting, through malnutrition and disease, as access to food, water and sanitation are denied or restricted.

Some 27 million children in conflict zones have been forced out of school.

“Children are being targeted and exposed to attacks and brutal violence in their homes, schools and playgrounds,” said Manuel Fontaine, Unicef’s director of emergency programmes. “As these attacks continue year after year, we cannot become numb. Such brutality cannot be the new normal.”

Much of the fighting affecting children occurred in long-running conflicts in Africa.

Across 2017:

• Boko Haram, the militant jihadist organisation active across Nigeria, Chad, Niger and Cameroon, forced at least 135 children to act as suicide bombers, nearly five times the number in 2016.
• Children have been raped, killed and forcibly recruited in the Central African Republic, after a surge in the sectarian conflict that has seized the country since a coup in 2013.
• Political and militia violence has driven more than 850,000 children from their homes in the Democratic Republic of the Congo, while more than 200 health centres and 400 schools have been deliberately attacked.
• In Somalia nearly 1,800 children were recruited to fight in the first 10 months of 2017, while in South Sudan more than 19,000 children have been recruited into armed groups since 2013.
• In Yemen three years of fighting has left at least 5,000 children dead or injured and 1.8 million are suffering from malnutrition.

“2017 was a horrible year for the children of Yemen,” Unicef’s Meritxell Relaño said from Sana’a.

Children have also been affected by conflict in the Middle East and in central and south-east Asia.

In Iraq and Syria children have reportedly been used as human shields, trapped under siege and targeted by snipers, while in Afghanistan nearly 700 children were killed in fighting in the first nine months of the year.

Rohingya children in Myanmar were subject to systematic violence and driven from their homes. More than half of the 650,000 Rohingya forced over the border into Bangladesh are under 18.

Unicef has called on all parties in conflicts to respect international humanitarian law and immediately end violations against children and the targeting of civilian infrastructure, including schools and hospitals. The agency also called on states with influence over non-state parties to conflict to use their influence to protect children.

Pope Francis, in his traditional Christmas message, drew attention to the plight of children in war zones. “We see Jesus in the children worldwide wherever peace and security are threatened by the danger of tensions and new conflicts,” he said, citing Syria, Iraq, Yemen and several African states.