The United Nations is calling on all parties in the Afghan conflict to take "urgent steps to halt the killing and maiming of civilians," as a new report reveals that conflict-related civilian casualties hit a record high in 2016.

One-third of those reported killed or wounded were children.

A total of 11,418 civilian casualties were reported last year -- a combined increase of 3 percent over the previous year, the UN Assistance Mission in Afghanistan (UNAMA) said in a report published on February 6.

The figure includes 3,498 people killed and 7,920 injured, according to the Afghanistan Annual Report On Protection Of Civilians In Armed Conflict.

The numbers recorded by the UNAMA's human rights team were the highest since the UN began systematically documenting civilian casualty figures in 2009.

Of these, 3,512 were children -- 923 dead and 2,589 injured -- up 24 percent from the previous year.

"The killing and maiming of thousands of Afghan civilians is deeply harrowing and largely preventable," said Tadamichi Yamamoto, the UN secretary-general's special representative for Afghanistan. "All parties to the conflict must take immediate concrete measures to protect the ordinary Afghan men, women and children whose lives are being shattered."

Antigovernment groups like the Taliban and Islamic State (IS) were responsible for almost two-thirds of the casualties, while pro-government forces were responsible for nearly one-quarter.

UN investigators attributed a total of 4,953 deaths and injuries to the Taliban.

They also documented a 10-fold increase in casualties from last year -- 899 deaths and injuries -- caused by IS militants, who last year launched an increasing number of suicide attacks. The majority of the casualties occurred in three large-scale attacks on the Shi'ite community in the latter half of 2016.

Afghan security forces caused about 20 percent of the casualties, while pro-government militias and international forces caused 2 percent each.

The report noted that as in 2015, ground engagements between antigovernment and pro-government forces remained the leading cause of civilian casualties, followed by improvised explosive devices and suicide attacks.

Air strikes carried out by Afghan and international forces caused 590 civilian casualties -- 250 deaths and 340 injured -- nearly double that recorded in 2015 and the highest since 2009.

UN High Commissioner for Human Rights Zeid Ra'ad al-Hussein said the casualty figures painted a picture of the most vulnerable sectors of society paying the highest price.

"Children have been killed, blinded, crippled -- or inadvertently caused the death of their friends - while playing with unexploded ordnance that is negligently left behind by parties to the conflict," Zeid said.

"Women continue to be brutally punished in parallel so-called 'justice' processes while religious minorities are targeted as they pray in their mosques."

In a statement, Zeid and Yamamoto called on all parties to minimize the use of explosive weapons in areas populated by civilians and to ensure explosive remnants of war are removed.

They also insisted on the need for accountability and justice for violations of international humanitarian law and human rights law.