WASHINGTON (CBS DC) — The Iraqi city of Ramadi fell to the Islamic State of Iraq and Syria because exhausted Iraqi forces were up against a “pretty good” force of militant fighters, according to Gen. John Allen.

The presidential envoy for the coalition fighting ISIS, Allen tells CBS News that “it’s going to take a long time” for Iraqi forces to get the Middle East region under control. This comes after comments last weekend from Defense Secretary Ash Carter, who angered some Iraqi officials when he said the Iraqi forces “showed no will to fight” ISIS in Ramadi.

“I believe the Iraqi military is going to combine its capabilities and ultimately liberate this country, it’s going to take a while to do that,” said Allen.

Asked by CBS News whether there is something that can be taught to the Iraqi forces, he said, “Will is about leadership; confidence. Will is about, as I said, amassing success, and that doesn’t come overnight. That comes over time, and that is part of the process of the professionalization of the development of the Iraqi security forces that we’re undertaking now.”

Allen said claims that a large number of Iraqi troops had fled instead of facing the significantly smaller force of ISIS militants is untrue. He confirmed U.S. Defense official estimates that there were about 10,000 Iraqi troops throughout the Anbar province, but said there were only roughly 2,000 such troops in Ramadi to face the 400 and 800 ISIS fighters.

Allen said the ISIS fighters at Ramadi are “pretty good, and the troops that they were fighting at that particular location had been fighting for a long time, and they were tired, they had not been well supported in recent battles. A relief column that was coming in turned around and went back because it was badly ambushed, so once again it was an issue that I believe was the effect of the local conditions on the ground at that particular moment….That’s not going to be the case everywhere.”

The ISIS fighters came at the Iraqi forces with an urban warfare tactic of sending vehicle-borne truck bombs laden with thousands of pounds of explosives attached.

Allen is set to meet in Paris with members of the coalition against ISIS to develop a strategy to defeat the militant faction with up-to-the-minute information as it changes on the ground. He dismissed suggestion that the Obama administration has an “Iraq first” strategy to deflect decisions when ISIS pulls back to a safe haven in Syria.

“No, it’s Iraq first and Syria at the same time. We’re doing work in Syria at the same time that we’re undertaking support of Iraq, so it’s not a purely sequential undertaking. Iraq is the main effort for the moment but there’s also shaping efforts underway in Syria to include the train and equip program so it is not sequential in that context.”

Allen said he agrees with many fellow veterans of the Iraq War who fought for Ramadi, saying he is “angry” the city fell back into ISIS’ control.

“There is no reason why I shouldn’t be,” he said. “Any of the Marines or soldiers that fought there, or…witnessed their units and their fellow soldiers or Marines give their lives there is going to have very strong feelings about this. And I had very strong feelings about this, which means for me, it’s a matter of now doubling down and helping the Iraqis to be successful.”