Defense Secretary Robert Gates is touring Afghanistan this week to gauge progress on the ground, but back in Washington, the Pentagon is already wrestling with what to do about the “significant” increase in the number and effectiveness of roadside bombs throughout the country.

Between June 2009 and 2010, insurgents’ use of improvised explosive devices, or IEDs, rose by 22 percent. More worrying, say senior US military officials, is that the rate of effective attacks – in other words, bombs that result in injuries to NATO troops or Afghan civilians – has increased 45 percent.

Lt. Gen. Michael Oates, director of the Pentagon’s Joint Improvised Explosive Device Defeat Organization, says there has been a “significant” rise in the number of roadside bombs because even as the US military has surged into Afghanistan, the Taliban has surged, too.

And paradoxically, Lt. Gen. Oates says, a lack of technological expertise among Afghans means the locally manufactured IEDs are of a simpler design than those deployed against US forces in Iraq, making them harder to detect by NATO troops and hence more effective.

In Iraq, the US military was accustomed to relatively sophisticated roadside bombs with military-grade munitions and remote detonators that were made with everything from walkie-talkies to children's toys. But in Afghanistan, Oates says, where literacy rates are low – in the single digits in some towns – there is a “degree of education and training” that is difficult to find, including among those inclined to build bombs.

Afghan bomb-makers also lack access to high-grade munitions. As a result, Oates says, the majority of bombs in Afghanistan today are made with simple ammonium nitrate, commonly found in fertilizer. The low metallic content in fertilizer-based bombs is “very difficult” to detect, he says, and much of the high-tech bomb-detection equipment that worked well in Iraq does not help in Afghanistan.

Help from Iran?

That said, Oates adds, Afghan insurgents do not appear to be getting much help from Iran in building bombs. It was Iranian-made roadside bombs in Iraq known as EFP’s, or explosively-formed penetrators, that were particularly lethal to US troops.

Oates says there is “nowhere near” the level of Iranian support for Afghan insurgents that commanders grappled with in Iraq. Though the US military has found “minor assistance” to insurgents from Iran, he says, “I don’t want to make more of that then there is.”

The reasons why this is the case are unclear, he says, but insurgents continue to find ways to injure and kill NATO troops. Though Afghan President Hamid Karzai has declared ammonium nitrate, and subsequently most fertilizers, illegal in Afghanistan, the material continues to be covertly brought over the border from Pakistan, where fertilizer is frequently used.

Ammonium nitrate bombs are large, and often put into culverts beneath the roads, occasionally with the help of wheelbarrows, for example. Because these homemade bombs are difficult to detect with machines, soldiers often must get out of their vehicles to look in the culverts, which run through roads every 100 feet in some areas. It's a time-consuming and dangerous endeavor.

What the Pentagon is doing

To combat the Afghan IEDs, Oates says, the Pentagon has increased the number of bomb-sniffing dogs on the ground, which, in partnership with well-trained soldiers, have proven “most effective” in finding fertilizer-based bombs.

The US has also increased the number of tethered blimps floating over its bases in Afghanistan. There are now almost 50 throughout the country, with “more coming,” says Oates. These blimps, which carry cameras to monitor roads and areas around the bases, became symbols to the Iraqi insurgency, which often made it a point of pride to shoot them down.

Many Iraqis mistakenly believed that the blimps, often called “aerostats” by the US military, had special cameras that could see through buildings and walls. When the blimps were not flying above US bases, for routine maintenance or because they were shot down, rates of violence in nearby towns often jumped.

The US military is hoping that the blimps will have a similar “behavior-modifying” impact in Afghanistan. In the meantime, US troops continue to hone their IED-detection techniques, to some effect. The number of roadside bombs that have been found and cleared has increased by 15 percent in the past year.

Dirt roads make detection difficult

But the lack of paved roads throughout the region continues to frustrate the US military as it is far more difficult to detect places where bombs are buried on dirt roads.

Along Afghanistan’s Route 1, a paved highway that connects many of the country’s major cities, the surge of US troops has been having an impact. Bombs have decreased on the heels of focused protection of the roads by US and Afghan troops. Three months ago, it was difficult to drive on the road without hitting a roadside bomb, Oates says. Today, Afghan commerce and traffic is returning.

But while many insurgent leaders have been driven out with the surge of troops “they are likely to return” with winter’s end, Oates says, and with them, a potential increase in the number of IEDs on the pivotal road.