The Save the Children International charity says at least 100,000 babies die every year because of armed conflict and related effects, with Afghanistan listed as among the 10 worst countries to be a child.
"Increasingly, the brunt of armed violence and warfare is being borne by children," the U.S.-based organization said on February 15 in its report, titled Stop The War On Children.
"Children suffer in conflict in different ways to adults, partly because they are physically weaker and also because they have so much at stake -- their physical, mental, and psychosocial development are heavily dependent on the conditions they experience as children."
It said that "many more children die in conflict as a result of malnutrition, disease, and lack of health care than from bullets or bombs."
In the five years from 2013-17 in the 10 worst-hit areas, it said, an estimated 550,000 infants died as a result of fighting and the "reverberating impact of conflict."
The figures "suggest that every year in just 10 conflict-affected countries, at least 100,000 infants die who in the absence of conflict would survive."
It listed the 10 worst countries for children in conflict areas as Afghanistan, Iraq, Syria, and Yemen, Central African Republic, Democratic Republic of Congo, Mali, Nigeria, Somalia, and South Sudan.
"In Afghanistan alone, the UN verified 3,179 child casualties," it said, referring to data for infants and older children for 2017.
"Many of these incidents involved improvised explosive devices and unexploded ordnance, accounting for at least 33 percent of those casualties."
The deaths include "children being used to plant bombs and/or to carry out the attacks themselves," the report said.
It estimated that nearly 90 percent of children in Yemen, 70 percent of those in Syria, and 60 percent of Somalia's children were living in close proximity to high-intensity conflict in 2017.
The report noted that the UN Security Council had identified six "grave violations" against children in situations of armed conflict: killing and maiming of children, recruitment and use of children as soldiers, sexual violence against children, abduction of children, attacks on schools and hospitals, and denial of humanitarian access.
Save the Children said that its investigations showed that the number of children directly affected by verified cases of grave violations in 2017 was more than 25,000, the highest ever recorded.
"The nature of conflict has changed, putting children in the front line in new and terrible ways," said Helle Thorning-Schmidt, the chief executive of Save the Children International.
"Wars are lasting longer. They are more likely to be fought in urban areas among civilian populations, leading to deaths and life-changing injuries, and laying waste to the infrastructure needed to guarantee access to food and water," she added.
