A homemade bomb exploded near a U.S. special operations convoy in eastern Afghanistan, but no casualties were reported, the U.S. military said Thursday.

The convoy was traveling about a half mile from a U.S. military base in the eastern town of Gardez (searchwhen the device exploded Wednesday, U.S. Lt. Col. Douglas Lefforge said in a statement from coalition headquarters at Bagram Air Base (search), north of the capital.

"The convoy continued to the (U.S.) fire-base and returned with other forces to investigate. There were no casualties and only a cracked windshield to one vehicle," Lefforge said.

There was no word on who might have set off the bomb, but several such explosive devices -- at least one of them set off by remote-control -- have detonated near U.S. forces in eastern Afghanistan amid stepped up rebel attacks in the area.

On Friday, a homemade bomb exploded near a U.S. special forces convoy south of Kabul (search), lightly wounding an Afghan soldier also traveling with them. And late last month, another homemade bomb exploded as a convoy of American soldiers passed near Gardez, lightly wounding a U.S. special forces soldier.

About 11,500 coalition troops, the majority of them American, are in Afghanistan carrying out operations in search of Taliban rebels and their allies. The Taliban were overthrown in a U.S.-led war in 2001.