The scale of attacks on children in the world's conflict zones reached shocking levels this year, the United Nations Children's Fund says.
In a new report, Unicef said all sides blatantly disregarded international laws designed to protect the most vulnerable.
The report highlights several conflict zones where it said children had suffered in the past year. It included:
- In the Central African Republic, children were killed, raped, abducted and recruited by armed groups in a dramatic increase in violence
- Islamist militants Boko Haram forced at least 135 children in north-east Nigeria and Cameroon to act as suicide bombers, almost five times the number in 2016
- Muslim Rohingya children in Myanmar suffered "shocking and widespread violence" as they were driven from their homes in Rakhine state
- In South Sudan, more than 19,000 children were recruited into armed forces and armed groups
- Fighting in Yemen has left at least 5000 children dead or injured according to official figures, with the real number expected to be much higher
- In eastern Ukraine 220,000 children are living under the constant threat from landmines and other unexploded devices left over from the war
The agency's deputy executive director Justin Forsyth said children were being particularly targeted.
"They're being used as human bombs by Boko Haram, as human shields. Much bigger numbers of children are being forced to be child soldiers, they're being raped, they're being enslaved.
"Recently in Libya I met children who had been enslaved on their way through Africa and arriving in Libya before coming into Europe.
"So there seems to be a real flouting of international humanitarian law on a huge scale."
The report says that in some places, children abducted by extremist groups suffer further abuse when they are released to security forces.
Millions more children suffer from malnutrition, disease and trauma when access to food, water, sanitation and health is prevented by fighting, it says.
Unicef director of emergency programmes Manuel Fontaine said such brutality "cannot be the new normal".
"Children are being targeted and exposed to attacks and brutal violence in their homes, schools and playgrounds," Mr Fontaine said.
The report put out a plea for organisations and countries to take action to stop children being targeted.
"Unicef calls 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," the reports adds.
"Unicef also calls on states with influence over parties to conflict to use that influence to protect children."