By David Morgan
WASHINGTON, Aug 6 (Reuters) - Roadside bomb incidents involving U.S. and NATO troops in Afghanistan hit their highest level in at least four years between April and June, the Pentagon said on Wednesday.
There was a peak of about 200 such incidents in Afghanistan in the three-month period, data released by a Defense Department office that oversees efforts to thwart attacks by improvised explosive devices, or IEDs, in Iraq and Afghanistan showed.
About 120 of the devices exploded, including some 40 that resulted in U.S. and NATO casualties, the data showed. Western forces discovered and cleared another 80 before they could be detonated by insurgents.
The number of roadside bomb incidents declined in June, the latest month for which data was available for Afghanistan, and officials said roadside bomb incidents were expected to fall further in July.
The spring peak coincided with an intensifying Taliban insurgency that has pushed U.S. military deaths in Afghanistan above those in Iraq in recent months.
The Pentagon did not release precise statistics on bomb incidents for security reasons and no comparative figures for other time periods were available.
But a chart depicting IED incidents in Afghanistan showed the spring peak to be the highest level since June 2004.
Army Lt. Gen. Thomas Metz, who heads the Pentagon effort to defeat IED attacks, attributed the rise partly to an increase in the U.S. and NATO troop presence in Afghanistan.
"Some of the numbers have to be attributed to just more coalition forces out there facing the enemy," Metz told reporters at a briefing.
The United States has 34,000 troops in Afghanistan, 16,000 of whom are under NATO command.
Meanwhile, the Pentagon said dramatic security gains helped drop the monthly average for roadside bomb incidents in Iraq by more than half in July from a high point early in 2007.
Declining IED incidents in Iraq came as the Bush administration reduced U.S. force levels to a current 144,000 troops with the withdrawal of five combat brigades deployed last year to quell sectarian violence.
Metz said the data included a drop in incidents involving Iranian-made explosively formed penetrators, which are capable of piercing heavy armor. The general said those devices account for five to 15 percent of IED incidents in Iraq but 40 percent of U.S. and coalition IED casualties. (Reporting by David Morgan, editing by Patricia Zengerle)