Canadian special forces exchanged gunfire with Islamic State fighters in Iraq in recent days, in the first confirmed ground battle between Western troops and IS, a senior officer said Monday.

The Canadians came under mortar and machine gun fire while training Iraqi troops near front lines and shot back in what Canadian special forces commander Brigadier General Michael Rouleau described as self-defense, killing the IS fighters.

Rouleau said the melee had taken place in the previous seven days and was "the first time we've taken fire and returned fire" in Iraq, where the extremists have overrun large areas.

"My troops had completed a planning session with senior Iraqi leaders several kilometers behind the front lines," Rouleau told a regular media briefing on the conflict.

"When they moved forward to confirm the planning at the front lines in order to visualize what they had discussed over a map, they came under immediate and effective mortar and machine gun fire."

The general said the Canadians used sniper fire to "neutralize both threats" and there were no Canadian injuries.

The United States has previously reported having launched an unsuccessful hostage-rescue operation against the IS group in neighboring Syria, but Western forces have not officially engaged in ground combat.

A US-led international coalition has been carrying out air raids on IS extremists in Iraq and Syria since last year. Canada is only involved in Iraq operations.

Canada sent some 600 air crew and other military personnel -- as well as six fighter jets and other military aircraft -- to the region in November to participate in the air strikes against the Islamic State.

The Canadian deployment is due to end in April, unless parliament votes to extend the mission.

There are also 69 Canadian special forces training and advising Iraqi troops on the ground, but theoretically not in combat.

Most of the instruction, a key plank of Western moves to defeat the emboldened IS group, takes place "well behind front lines," Rouleau noted.

The Islamic State group gained international notoriety last August when its fighters and those from other militant groups swept through the northern Iraqi city of Mosul, then overran swaths of territory north and west of Baghdad, threatening to overrun the capital.

Western governments fear IS could eventually strike overseas, but their biggest immediate worry was its gains in Iraq and Syria, and the likely eventual return home of foreign fighters.

US President Barack Obama has outlined plans for the broad international coalition to "significantly degrade" the group in Iraq and Syria.

The coalition air strikes in Iraq and Syria have targeted IS fighting positions, heavy weapons and buildings used to store weapons.

Lieutenant General Jonathan Vance said the Islamic State "has been stopped (in Iraq) and they are unable to mount broad offensive operations that would somehow change the situation dramatically."

But, he added, using another acronym for IS, "a large-scale reversal of ISIL's position in Iraq has yet to come."

Using aerial maps, he pointed out "relatively modest areas where the tide has turned and Iraqi forces are in control of the area."