Pentagon chief and US Defence Secretary Ashton Carter said on 24 May that despite Iraqi forces having the capacity to fight off IS, they still "failed to fight" in Ramadi due to lack of "will".
"What apparently happened was the Iraqi forces showed no will to fight. They were not outnumbered, and they vastly outnumbered the opposing force, and they failed to fight and withdrew from the site," Carter told CNN's State of the Union.
"We can give them training, we can give them equipment - we obviously can't give them the will to fight.
"We can participate in the defeat of IS. But we can't make Iraq... a decent place for people to live. We can't sustain the victory, only the Iraqis can do that. And, in particular in this case, the Sunni tribes to the west."
Meanwhile, Iraq's defence and security committee called the comments "unrealistic and baseless".
Speaking to the Associated Press, Hakim al-Zamili, the head of Iraq's parliamentary defence and security committee, criticized the US for failing to provide, "good equipment, weapons and aerial support" during the Ramadi fighting, reported BBC News.
Zamili condemned the US for trying to, "throw the blame on somebody else."
According to the US claims, Iraqi forces left several tanks, artillery and armoured personnel during the fall of Ramadi.
Iraqi forces have now deployed Shia militias in the area in an attempt to push back IS.