The United Nations children's agency UNICEF declared 2014 a devastating year for children with as many as 15 million caught up in conflicts around the world.
UNICEF Executive Director Anthony Lake said the high number of crises meant many of them were quickly forgotten or failed to capture global headlines, such as in Afghanistan, Somalia, Sudan and Yemen.
Globally, UNICEF said around 230 million children were living in countries and regions affected by armed conflict.
"Children have been killed while studying in the classroom and while sleeping in their beds; they have been orphaned, kidnapped, tortured, recruited, raped and even sold as slaves," Mr Lake said in a statement.
"Never in recent memory have so many children been subjected to such unspeakable brutality."
Significant threats also emerged to children's health and well-being like the deadly outbreak of Ebola in the west African countries Guinea, Liberia and Sierra Leone, which has left thousands orphaned and around five million out of school.
"Violence and trauma do more than harm individual children -they undermine the strength of societies," Mr Lake said.
In Central African Republic, where tit-for-tat sectarian violence has displaced one-fifth of the population, some 2.3 million children are affected by the conflict with up to 10,000 believed to have been recruited by armed groups during the pasty ear and more than 430 killed or maimed, UNICEF said.
Some 538 children were killed and 3,370 injured in Gaza during a 50-day war between Israeli troops and Hamas militants, it said.
In Syria, UNICEF said more than 7.3 million children have been affected by the civil war, including 1.7 million who fled the country.
In neighbouring Iraq an estimated 2.7 million children have been affected by conflict, it added, with at least 700 believed to have been maimed or killed this year.
"In both countries, children have been victims of, witnesses to and even perpetrators of increasingly brutal and extreme violence," UNICEF said.
Some 750,000 children have been displaced in South Sudan with 320,000 living as refugees.
The United Nations said more than 600 children have been killed and more than 200 maimed this year, while some 12,000 are being used by armed groups.