The US military said on Tuesday that the attack occurred while the troops were on a routine patrol in support of an ongoing operation near Ghazni, south of the capital.
Spokesman Lieutenant Colonel Jerry O'Hara said none of the injuries appeared to be life-threatening.
US aircraft were sent to the scene to transport the wounded to hospital, he said.
"Terrorists, who often pay impoverished Afghans to detonate these devices for them, are behind these brutal attacks," said O'Hara.
"These criminals know they cannot stand up to Afghan and coalition forces, so they are forced to resort to these tactics."
On Monday, a bomber wounded four US troops in an assault on an American military convoy just west of Kandahar.
O'Hara said three bombs were discovered and destroyed in other locations on Monday.
Meanwhile, Afghan and US-led coalition forces killed two suspects and captured 13 others in a firefight in southern Afghanistan, the US military said.
US-led forces killed two in a
firefight on Monday
A military statement said the clash occurred on Monday after the 15 rebels were spotted walking through a narrow valley just north of Kandahar, the main city in southern Afghanistan.
Also on Monday, police in Kandahar arrested an alleged local Taliban commander, Mohammed Eisah, who is suspected of involvement in the killing in May of Abdul Fayaz, a top cleric in southern Afghanistan, as well as the assassination last year of a regional army commander.
A local police chief said Eisah was captured after a firefight near the city.
In addition to Eisah, two Afghan men and two women were arrested at a police checkpoint near Kandahar after they were found to be carrying weapons and photos of Osama bin Laden and renegade former premier Gulbuddin Hekmatyar.