None of the injuries appeared to be life-threatening, and U.S. aircraft were sent to the scene to transport the wounded to a hospital, said spokesman Lt. Col. Jerry O'Hara.
The attack occurred during a routine patrol in support of an ongoing operation south of Ghazni, south of the capital, O'Hara said.
"Terrorists, who often pay impoverished Afghans to detonate these devices for them, are behind these brutal attacks," he said. "These criminals know they cannot stand up to Afghan and coalition forces, so they are forced to resort to these tactics."
On Monday, a suicide bomber wounded four U.S. troops in an assault on an American military convoy just west of the city. O'Hara said three bombs were discovered and destroyed in other locations Monday.
Meanwhile, Afghan and U.S.-led coalition forces killed two suspected insurgents and captured 13 others in a firefight in southern Afghanistan, the U.S. military said.
The clash occurred Monday after the 15 rebels were spotted walking through a narrow valley just north of Kandahar, the main city in southern Afghanistan, a statement said.