Afghan civilian casualties hit 'record high' in 2016
Around 11,500 of 2016's casualties were of civilians, a third of whom were children killed or wounded.
Fighting between Afghan security forces and militants remained the "leading cause of civilian casualties" more than two years after NATO's combat mission in Afghanistan ended, said the UN.
"It is about time the various parties to the conflict ceased the relentless commission of war crimes and thought about the harm they are doing to their mothers, fathers, children and future generations by continuing to fuel this senseless, never-ending conflict," said Zeid Ra'ad al-Hussein, the UN High Commissioner for Human Rights.
The United Nations Assistance Mission in Afghanistan [UNAMA] recorded 11,418 civilian casualties [3,498 deaths and 7,920 injured], an increase of three percent on 2015.
More than 3,500 children were among the victims, representing a "disproportionate" increase of 24 percent in one year, the report said.
Many of the civilian casualties were caused by unexploded munitions.
The UN's special envoy to Afghanistan, Tadamichi Yamamoto, described the new data as "deeply harrowing," highlighting "the gruesome reality of the conflict".
He called on both pro and anti-government forces to cease fighting in densely populated areas and to stop using schools, mosques and other civilian buildings for military purposes.
"The continuation of attacks targeting civilians and indiscriminate attacks by anti-government elements, in particular, IED and suicide attacks in civilian-populated areas, is illegal, reprehensible and, in most cases, may amount to a war crime," the report said.
"It is imperative that the perpetrators, whoever they are, be held accountable for such acts."
The majority of civilian casualties detailed by the report were recorded in Kabul province. This was followed by Helmand, Kandahar, Nangarhar, Uruzgan, Kunduz and Fayrab provinces, the mission's human rights director Danielle Bell said.
Last year also saw 590 civilian casualties caused by airstrikes - the highest number yet.
This figure is almost double that of 2015, with women and children in populated areas often being the victims.
Since the UN launched its annual report eight years ago, the conflict has claimed 24,841 civilian lives and injured 45,347, the report said.
More than 60 percent of the casualties in 2016 were attributed to "anti-government elements," mainly the Taliban, while 24 percent were attributed to pro-government forces.