US Central Command (CENTCOM) said fighter jets and drones had destroyed or damaged four armored personnel carriers, seven armed vehicles, two Humvees and an armored vehicle.
CENTCOM "conducted these strikes under authority to support humanitarian efforts in Iraq, as well as to protect US personnel and facilities," it added.
"All aircraft exited the strike areas safely."
Kurdish forces attacked the Islamic State (IS) fighters who wrested the Mosul dam from them a week earlier, a general told AFP.
"Kurdish peshmerga, with US air support, have seized control of the eastern side of the dam" complex, Major General Abdulrahman Korini told AFP, saying several militants had been killed.
Buoyed by the air strikes US President Barack Obama ordered last week, the peshmerga fighters have tried to claw back the ground they lost since the start of August.
The dam on the Tigris provides electricity to much of the region and is crucial to irrigation in vast farming areas in Nineveh province.
The recapture of Mosul dam would be one of the most significant achievements in a fightback that is also getting international material support.
The strikes took place just a day after IS militants carried out a "massacre" of dozens of villagers.
The Islamic State militant group has executed 700 members of a tribe it has been battling in eastern Syria during the past two weeks, the majority of them civilians, a human rights monitoring group said on Saturday.
The Syrian Observatory for Human Rights, which has tracked violence on all sides of the three-year-old conflict, said that reliable sources reported beheadings were used to execute many of the al-Sheitaat tribe, which is from Deir al-Zor province.
The conflict between Islamic State and the al-Sheitaat tribe, who number about 70,000, flared after Islamic State took over two oil fields in July.
"Those who were executed are all al-Sheitaat," Observatory director Rami Abdelrahman said by telephone from Britain. "Some were arrested, judged and killed."
Reuters cannot independently verify reports from Syria due to security conditions and reporting restrictions.
AFP and Reuters contributed to this report