Taliban fighters more than doubled the number of homemade bombs they used against U.S. and NATO forces in Afghanistan last year, relying on explosives that are often far more primitive than the ones used in Iraq.
The embrace of a low-tech approach by Taliban-trained bombmakers — they are building improvised explosive devices, or IEDs, out of fertilizer and diesel fuel — has stymied a $17 billion U.S. counteroffensive against the devices in Iraq and Afghanistan, military officials say. Electronic scanners or jammers, which were commonly deployed in Iraq, can detect only bombs with metal parts or circuitry.
"Technology is not going to solve this problem," said Army Lt. Gen. Michael Oates, director of the military's Joint IED Defeat Organization, or JIEDDO. "I don't think you can defeat the IED as a weapon system. It is too easy to use."
U.S. military officials said they expected the number of IED attacks to climb further this year as 40,000 U.S. and NATO reinforcements pour into Afghanistan.
Oates said technological advances have enabled the military to save lives by providing better armor and other forms of protection for troops. But he said the high-tech approach — despite billions of dollars in research — had failed to produce an effective way to detect IEDs in the field. About four-fifths of the devices that are found before they explode are detected the old-fashioned way: by troops who notice telltale signs, such as a recently disturbed patch of dirt that might be covering up a bomb.
Despite insurgents' crude approach, the explosive power of their IEDs is growing. Each bombing in Afghanistan, on average, causes 50 percent more casualties than it did three years ago, Oates said Wednesday at a House committee hearing. U.S. officials say even armored troop-transport vehicles that were designed to protect against roadside bombs are now vulnerable.
All told, the U.S. military recorded 8,159 IED incidents in Afghanistan in 2009, compared with 3,867 in 2008 and 2,677 the year before.
Last month, 721 IEDs blew up or were defused in Afghanistan, slowing a major Marine-led offensive in Helmand province and killing 28 U.S. and allied troops. These bombs are the leading cause of U.S. casualties by a large margin.
The number of IED attacks in Iraq, meanwhile, has plummeted, mirroring the overall decrease in violence in that country. At their peak, in 2007, Iraqi insurgents employed 23,000 IEDs. Last year, that number fell to about 3,000, according to U.S. military figures.
Oates credited U.S. countermeasures — such as interrupting the flow of military-grade explosives and detonators from Iran — for some of the decrease. Other military officials said a bigger factor was the overall reduction in the intensity of the insurgency; as sectarian fighting faded, people simply stopped planting bombs.
Maj. Gen. Michael Flynn, the head of U.S. military intelligence in Afghanistan, has said that the most effective way to combat the flood of IEDs is to embrace an overall counterinsurgency strategy. If U.S. and NATO forces can win the support of the local population, the thinking goes, the bombings will stop.
But with the number of IED attacks soaring in Afghanistan, Defense Secretary Robert Gates created a task force in November to devise more short-term solutions for responding to the threat. He gave the group six months to come up with recommendations.
"There's no doubt the urgency has picked up," said Oates, who took over as director of JIEDDO in January and sits on the task force. "We don't have years to wait to start changing the momentum in Afghanistan."
JIEDDO, which has a staff of about 3,500, was created in 2006 after U.S. commanders in Iraq said they needed a major research effort to come up with ways to fight IEDs. Some military officials likened the campaign to a modern-day Manhattan Project, the code name for the secret program that developed the first atomic bomb.
Congress has spent nearly $17 billion on IED research and training programs, not including money allocated for armored vehicles and other equipment to protect troops.
In Iraq, in addition to using electronic jammers, the U.S. military employed a range of tactics to detect IEDs. Unmanned aircraft and blimps armed with cameras roamed the skies to look for insurgents as they placed bombs along roadsides and under bridges.
But experts said those tactics are only marginally useful in Afghanistan. Because of the country's mountainous terrain, surveillance drones have a harder time spotting bombers at work. Unlike in Iraq, most of the roads are unpaved, making it more difficult to detect bombs buried in the dirt.
"It's just a tough environment," said Command Sgt. Maj. Todd Burnett, who oversees training programs for JIEDDO. "It's the harshest conditions imaginable for a soldier."