Afghan men assist an injured man after a suicide bombing at the gate to a NATO compound in Kabul, Afghanistan, Tuesday, July 2, 2013. (Rahmat Gul/AP)

The United Nations reported Wednesday that 23 percent more Afghan civilians were killed or injured in the first half of 2013 than during the same period last year, a finding that raises troubling questions about the Taliban’s ability to terrorize Afghanistan as the pace of the U.S. military withdrawal quickens.

The U.N. Assistance Mission in Afghanistan reported 1,319 deaths and 2,533 injuries among civilians, attributing most of them to the insurgency’s increased use of improvised explosive devices and to firefights in which civilians are targeted or become collateral damage. Casualties among women and children increased by 38 percent, the report said.

The sharp increase in casualties coincides with the first fighting season in which Afghan soldiers and police have been doing the bulk of the fighting. Those security forces also have suffered unprecedented losses. More than 2,750 police officers have been killed in the past four months, according to the nation’s interior minister.

The finding “demands even greater commitments and further efforts by all parties to the conflict to protect civilians, who are increasingly being killed and injured in the crossfire,” said Georgette Gagnon, the U.N. human rights director in Afghanistan.

The Taliban was quick to respond to the U.N. report, describing it in a statement as “an attempt of propaganda against Mujahideen.”

The statement also disputed that all those whose deaths were tallied in the report were civilians.

Despite improvement in the Afghan security forces and despite the Taliban’s inability to take over large urban centers such as Kabul, the rise in civilian casualties helps explain the widespread lack of public confidence in Afghanistan’s future as the U.S. and NATO forces withdraw. By February 2014, about half of the 68,000 U.S. troops in Afghanistan are due to leave.

“Unfortunately, the Taliban’s demonstrated lack of regard for human life has resulted in nearly 90 percent of all civilian casualties so far this year,” said Erin Stattel, a spokeswoman for the U.S.-led International Security Assistance Force (ISAF).

U.S. commanders note that most of the violence in Afghanistan occurs in places where less than a quarter of the country’s population lives. It’s in those districts and villages that the Afghan army is fighting its most heated battles, often disrupting Taliban activity without gaining ground, they say.

Gen. Sher Mohammad Karimi, the Afghan army’s chief of staff, said in a recent interview that his army lacks the manpower to defeat the insurgency every­where.

“I cannot cover every inch of the country,” he said. “The Afghan army isn’t big enough.”

The U.N. report counted 362 casualties — 146 civilian deaths and 216 civilian injuries — caused by the Afghan security forces or the ISAF. That marked a 16 percent drop in civilian deaths attributed to “pro-government” forces but a 58 percent increase in injuries compared with last year, the report said.