Sunday's CF-18 airstrikes destroyed construction equipment that ISIL fighters were using to develop defensive positions near Fallujah, west of Baghdad, Lt.-Gen. Jonathan Vance told a news conference in Ottawa.
The militants were also reshaping a local dam, flooding nearby land to force Iraqi forces on to roads that had been mined and to deny a water supply to local civilians, Vance said.
Iraqi troops have been conducting a localized offensive in the area since late September.
The New York Times reported over the weekend that a major counter-offensive by Iraqi forces, backed by American advisers and coalition air power, won't begin until the spring.
The goal will be for Iraqi and Kurdish Peshmerga fighters to cut off the enemy's Syrian supply routes, isolating them in strongholds such as Mosul before they can driven out — something that likely won't happen until the end of next year.
"The fight against ISIL in Iraq will be led by the Iraqis themselves and that is why we are actively supporting them," Vance said.
He didn't speculate on how long the fight will take, but a top American commander — U.S. Gen. Ray Odierno — recently told CNN he sees it taking up to four years.
"It's absolutely clear Iraqi forces want to begin their offensive operations as soon as they can," said Vance, who added that he "honestly doesn't have a good answer as to how long (the overall campaign) will take."
How many bombs were dropped and whether any ISIL fighters were killed in Sunday's raid were subjects Vance was not prepared to talk about, but he did say he was confident there were no civilian casualties.
Detailed planning is still underway among allies, who are considering a mission to train not only thousands of regular Iraqi army troops, but also local police officers and Iraq's version of a national guard.
A training mission could take between six months and a year, Vance noted.
The Harper government has yet to say whether it would consider taking part in such a training mission beyond the advise-and-assist role being played by a few dozen Canadian special forces troops in northern Iraq.
Thus far, Canada has not been asked by allies to consider joining bombing ISIL targets in Syria.
Since operations began late last week, the fighter-bombers have flown 18 missions and the two CP-140 Aurora planes have carried five surveillance flights, one of which led to several coalition airstrikes on an ISIL staging base at Al-Qaim, along the Syria border.
The U.S. military reported four bombing runs there on Sunday, taking out four ISIL vehicles and four buildings, which Vance described as a major supply hub and staging base for the extremist movement.
Although there is concern about the appearance of modern anti-aircraft weapons on the battefield, none have been used against Canadian jets, which are capable of avoiding them in any event, he added.
ALSO ON HUFFPOST: