In this file photo taken Tuesday, Aug. 27, 2013, Afghan army soldier Ali Raza, 30, searches for land mines with a metal detector during an IED (improvised explosive device) defusing training exercise in Jalalabad, east of Kabul, Afghanistan. (Rahmat Gul/AP)

U.S. and coalition forces have spent billions of dollars training and equipping Afghan security forces. But despite that, they are still struggling to get the Afghans to stand up to their most persistent foe: improvised explosive devices.

Now, the U.S.-led coalition is deploying a “mini-surge” of trainers and equipment to combat the lethal IEDs, which range from pipe bombs to powerful explosives that can leave trailer-size craters on roads.

The coalition’s efforts have run into complications, including the high Afghan illiteracy rate and the slow distribution of protective gear. Above all, the plans for training Afghan troops have been jolted by President Hamid Karzai’s resistance to signing a bilateral security agreement that would permit a residual U.S. military force to remain in Afghanistan after 2014.

Coalition commanders are now racing to complete a task that analysts say should have been done far sooner.

“Already, there is a bigger training gap to fill than we saw in Iraq, and it’s getting started later,” said James M. Dubik, a senior fellow at the Institute for the Study of War and a former commander of the NATO training mission for Iraq’s security forces.

Maj. Gen. Dean J. Milner, a Canadian who oversees the NATO Training Mission — Afghanistan, said the IED training program had not been an earlier priority because of the strain associated with recruiting and housing the 183,000-member Afghan National Army.

“There are a lot of things needed to build an army,” Milner said.

Although generally not as sophisticated as the military-grade explosives used against U.S. forces during the Iraq war, the Afghan bombs — made of cans, barrels and bags filled with ammonium nitrate and fuel — are responsible for a sharp increase in the number of Afghan dead and wounded.

Afghan military officials say IEDs cause 80 percent of the army’s casualties. Although the Afghan government doesn’t release annual casualty figures from the conflict with the Taliban, U.S. military statistics show that 1,163 Afghan soldiers were killed last year and more than 6,000 were wounded, according to the special inspector general for Afghan reconstruction. The death toll from IEDs for the 151,000-member Afghan police is thought to be even higher.

The IEDs are also increasingly killing civilians. A recent U.N. report documented 962 civilian deaths and nearly 2,000 injuries from improvised bombs last year, a 14 percent increase from 2012. One in three civilian deaths in Afghanistan is now caused by an explosive device, the U.N. report said.

Behind the ‘mini-surge’

After U.S. military commanders were stunned by the effectiveness of insurgents’ IEDs in Iraq, they developed new armored vehicles and stressed the importance of bomb detection and disposal.

Afghan soldiers, however, often travel in lightly armored Humvees, while Afghan police patrol in Ford Ranger pickup trucks. Afghan commanders say that despite the recent infusion of equipment, soldiers still lack robots, protective suits, jammers and night-vision goggles.

With the Afghan army also lagging in explosives experts, its members often resort to jerry-rigged tactics to locate and defuse IEDs, officials say.

“They have a bit of a cowboy attitude, like our own troops would in learning a new process,” U.S. Brig. Gen. Michael C. Wehr, the Joint Command deputy chief of staff engineer for the coalition, said in a recent interview.

Caroline Kennedy, director of the Centre for Security Studies at the University of Hull in England, said coalition counter-IED training lagged because international forces were “preoccupied” with the threats facing their own troops earlier in the war.

In 2010, during the height of the U.S.-led “surge,” roadside bombs killed 368 coalition troops, according to iCasualties.org. Coalition casualties from the explosive devices have decreased dramatically in recent years as Afghan forces have taken control of most security operations.

“I don’t think it was a deliberate omission; I think [the coalition] was just struggling hard to make sense of the new battlefield,” Kennedy said. Now, she said, the coalition “recognizes in very clear terms what needs to be done to prepare” the Afghan forces.

The mini-surge focused on IEDs began last fall. At the time, coalition commanders were especially concerned that there could be a spike in attacks because of the upcoming national elections and the planned withdrawal of coalition troops.

In October, dozens of U.S. Army explosive-ordnance-disposal specialists were sent to Afghanistan to help train its military. Their arrival coincided with the delivery of 20,000 pieces of equipment to the Afghan military, including hand-held mine detectors, armored tactical vehicles, probes and bomb-disposal suits, Milner said. The U.S. government paid for most of it.

Milner said much of the equipment had been ordered years ago. The delivery was delayed by U.S. and international laws governing weapons sales, as well as the difficulties associated with safely transporting armored material through Afghanistan, he and other coalition officials said.

In January, a coalition-funded counter-IED school opened in Kabul for Afghan police, complementing a German-supported training school for the Afghan military in the north. With help from the U.S. Army and contractors, the number of students in explosives-training courses tripled over the winter at Camp Shaheen, an Afghan base on the outskirts of Mazar-e Sharif.

But though the U.S.-run course began with 83 students, it ended in mid-February with about 35 graduating.

The high dropout and failure rates were partially attributed to Afghanistan’s low literacy rate — about 50 percent for men — and the challenge in getting soldiers to comprehend basic science and math. Some of the students also left the program upon realizing the danger involved in defusing IEDs.

In addition, the U.S. military trainers ran into difficulty finding translators skilled enough to render words such as “blasting cap” and “detonator” in Dari and Pashto.

Taliban targets

Still, over the past six months, the coalition has helped the Afghan army and police establish 327 explosive ordnance teams, Milner said. Afghan forces defuse 50 to 85 IEDs per day, said Gen. M. Zahir Azimi, a spokesman for the Afghan Defense Ministry.

But Auliya Atrafi, a deputy district governor of the Nad Ali area of Helmand province, estimates that thousands of IEDs remain in his community. And the soldiers who have been trained to detect the devices are increasingly being targeted by the Taliban, whose fighters rig bombs to explode while they are being dismantled, he said.

At the military hospital at Camp Shaheen, not far from where the IED-defusing training was held, the toll of the bombs was evident. In one room of the new hospital, half a dozen soldiers and police officers were in bed recovering from wounds suffered in roadside bombings.

Sharifuddin, a 25-year-old police officer, said he barely remembers what happened when an explosive device blew up beneath his vehicle last month.

“It just went off,” he said. The explosion killed his colleague and shattered the bones in Sharif­uddin’s legs. “There was nothing we could do.”