More than 900 children were killed in Afghanistan's conflict last year, the United Nations said, in the most violent year for children since it started keeping records.
The UN mission said the near-25% increase in child deaths from the previous year was largely caused by mines and munitions left over from decades of conflict.
It documented a 66% increase in such deaths in 2016.
The United Nations Assistance Mission in Afghanistan (Unama) said in its annual report: "Conflict-related violence exacted a heavy toll on Afghanistan in 2016, with an overall deterioration in civilian protection and the highest-total civilian casualties recorded since 2009, when Unama began systematic documentation of civilian casualties."
It said 3,498 people were killed in 2016, including 923 children, and that another 7,920 people were wounded.
The overall casualty toll was slightly higher than the previous year.
"I am deeply saddened to report, for yet another year, another increase in civilian casualties, another all-time high figure," Tadamichi Yamamoto, the UN envoy to Afghanistan, told a press conference.
Save the Children said the latest figures were "extremely concerning," and called on all parties to do more to protect civilians.
The Taliban, who have been waging an insurgency against the US-backed government in Kabul for more than 15 years, advanced on a number of fronts in 2016.
Afghan forces have struggled to tackle the militants since the US and Nato formally concluded their combat mission at the end of 2014.
Save the Children's country director, Ana Locsin said: "The humanitarian situation across much of Afghanistan has deteriorated significantly in the past 12 months.
"With the start of the traditional fighting season not far away with the end of winter, it could get even worse in the coming months."