Roadside bombs killed 268 American troops in Afghanistan last year, a 60 percent increase over the previous year even as the Pentagon employs new measures to counter the Taliban's makeshift weapon of choice.
The number of U.S. troops wounded by improvised explosive devices also soared, according to U.S. defense figures obtained Wednesday.
There were 3,366 U.S. service members injured in IED blasts -- up 178 percent from the 1,211 hurt by the militants' crudely made bombs in 2009, the figures showed.
Defense officials attributed the rise in casualties to the surge in U.S. forces in Afghanistan last year. Fighting has increased, especially in southern and eastern Afghanistan, as coalition forces work to weaken the Taliban in their strongholds and keep them from returning in force this spring.
The Pentagon's Joint Improvised Explosive Device Defeat Organization, based outside Washington, D.C., said not all the year-end statistics were gloomy.
During heavy fighting in June and July, 35 percent of the bomb blasts killed or wounded U.S. troops. That percentage fell to 26 percent in December despite ongoing violence and a high volume of IED attacks.
Since the U.S.-led invasion in October 2001, 619 U.S. troops have been killed and 5,764 have been wounded in roadside bomb attacks in Afghanistan, according to the Pentagon figures. Overall, 1,370 U.S. troops have been killed in Afghanistan since the war began.
Last year was by far the deadliest for all foreign troops, including Americans, with 702 killed, eclipsing the 2009 record of 504.
During a trip to Afghanistan in July, U.S. Undersecretary of Defense Ashton Carter said Washington was spending $3 billion on equipment to combat the threat of roadside bombs.
Last year, for instance, the Pentagon provided $495 million to buy 34 tethered surveillance blimps that give troops a bird's eye view of certain areas and sent in more unmanned surveillance aircraft so route-clearance patrols would have the benefit of full-motion video.
Meanwhile, President Hamid Karzai, acting under heavy Western pressure, inaugurated the country's new parliament on Wednesday. The swearing-in took place more than four months after a fraud-riddled vote for the lower house, with no resolution in sight of conflicting claims over the election's validity. Karzai urged members to work together but he took a swipe at his Western patrons for their "interference."