Defence officials said on Friday that American forces followed standard procedures and committed no misconduct.
Police in the town 100km north of Baghdad, said six adults and five children were shot dead in a US military raid on a home on March 15.
But the US military maintained that there were four dead in the incident, including a guerrilla, two women and a child, and they died after troops were fired upon from the house as they arrived to arrest an al-Qaeda suspect.
The defence officials, speaking on condition of anonymity, said an investigation found no wrongdoing by US forces.
The Army's Criminal Investigation Division reviewed the results of the investigation and found no reason to probe it further, the officials said.
The allegations of a massacre surfaced after the BBC aired footage of the incident on March 15.
The BBC said the images seemed to contradict US accounts of what happened in the town of Ishaqi.
The US army initially said four people had died during a raid to find an al-Qaeda supporter in which a building collapsed.
However, Iraqi police said 11 civilians, including five children and four women, were shot and killed by US troops who then blew up the building.
The video footage shows a row of bodies, many displaying what seem to be gunshot wounds.
The video was obtained from a Sunni group opposed to US-led forces, the BBC said.
The allegation came as a US military investigation into the killings of 24 Iraqi civilians by marines in the town of Haditha in November is expected to conclude that troops lied to their superiors, who did not fully investigate the allegations.