Children are being deliberately targeted in conflicts around the world at a "shocking scale", the head of the UN children's agency has warned.
The last 12 months have seen youngsters used as tools of war in conflicts including in Iraq, Syria and Yemen, Nigeria, South Sudan and Myanmar.
Many have died or been maimed in attacks on their homes and schools, while others have been used as human shields, subjected to rape, enslaved, or ordered to fight in militias against their will.
Millions have been directly harmed as fighters flout laws intended to protect innocents, said Manuel Fontaine, the UNICEF Director of Emergency Programmes.
Over the course of 2017, children in Syria and Iraq have reportedly been used as human shields, targeted by snipers and suffered intense bombardments on their homes and schools.
Youngsters living in rebel-held areas trapped under siege have lived through waves of intense bombings as food and medical supplies run short.
In Afghanistan, almost 700 children were killed in the first nine months of the year.
In Yemen, nearly 1,000 days of fighting left at least 5,000 children dead or injured, according to verified data, though the actual numbers expected to be much higher.
More than 11 million children in the country need humanitarian assistance, with 1.8 million children suffering from malnutrition and 385,000 at risk of death from starvation.
Rohingya children in Myanmar have also been deliberately targeted in a campaign of shocking and widespread violence that has seen hundreds of under-18s killed and families forced to flee their homes in Rakhine state.
Children have been killed, raped, abducted and recruited by armed groups amid a dramatic upsurge in violence over recent months in the Central African Republic.
Terrorist group Boko Haram has also targeted youths in northeast Nigeria and Cameroon. The militants have forced at least 135 children to act as suicide bombers, almost five times the number in 2016.
Violence in the Kasai region of the Democratic Republic of the Congo has driven 850,000 children from their homes, while more than 200 health centres and 400 schools attacked.
In South Sudan, where conflict and a collapsing economy led to a famine declaration in parts of the country, more than 19,000 children have been recruited into armed forces and armed groups.
Over 2,300 children have been killed or injured since the conflict first erupted in December 2013.
Children have also been targets of violence in Ukraine, where fighting is taking place in the East between government forces against separatist militias and Russian forces.
Around 220,000 children live under constant threat of mines and other explosive remnants of war due to the 500 kilometer 'contact line' – the strip of land where fighting is most severe –becoming one of the most mine-contaminated places on earth.
The children's agency concluded that 2017 was a "nightmare year" for young people trapped in conflict zones.
As well as those who were directly drawn into violence, millions more have suffered the loss of their homes, malnutrition, and been deprived of the chance to play and study.
UNICEF has called on all parties to conflict to abide by their obligations under international law to immediately end violations against children and the targeting of civilian infrastructure, including schools and hospitals.