OTTAWA -- The Canadian military insisted Thursday that its bombing campaign in Iraq is being conducted according to international law, which means there are some targets that Canada's aircraft will not hit.

However, Navy Capt. Paul Forget, a spokesman for the country's operations command, said Thursday there's no way to know for certain if Canada's most recent two missions caused any civilian casualties.

Previous military briefings on the Iraq mission have made it crystal clear that civilians were not harmed, but Thursday's was different: Forget said the latest targets -- a building and enemy positions -- make it impossible to say for sure.

"I can't guarantee anything when it comes to buildings," he said. "I can tell you the process (of selecting targets) is carried out very rigorously."

The attacks this week north of Baghdad involved the flattening of a roadside bomb-making warehouse near Mosul and the destruction of fighting positions, including trenches and possibly a bunker, near Kirkuk.

The military did not specify where in relation to Mosul, Iraq's second-largest city, the warehouse was located or how close it was to populated areas. The strike near Kirkuk took place in the desert, likely away from homes and businesses.

Forget wouldn't comment further on this week's strikes, except to say they are part of ongoing operations involving Iraqi ground forces.

The Australian air force confirmed a few weeks ago that it waved off at least one bombing mission because pilots and military planners were concerned about civilians in the area.

Forget was unable to say whether Canadian jets had aborted any missions.

He also refused to discuss if the military had been able to confirm whether any of Canada's raids had killed fighters from the Islamic State of Iraq and the Levant. The air force is more concerned with military "effects," such as clearing a path for local troops.

Forget also wouldn't talk about what targets are off-limits for Canada's CF-18 fighters, which have conducted four strike missions in Iraq so far.

Coalition aircraft have been hitting a variety of military and economic targets, everything from tanks and trenches to enemy training camps and oil refineries.

He insisted that the Islamic State's ability to conduct further offensive operations has been blunted and highlighted recent gains of Iraqi troops, who've retaken the key oil refinery at Bayji, north of Baghdad.

The briefing, which the Harper government has conducted once a week since the combat mission began, also showcased construction at the Canadian camp in Kuwait where pilots and other military support staff are housed.

Forget noted that work to improve the facility, including fibre optic cables and a maintenance shed for the CF-18s, had progressed.

The mission, at the moment, is authorized to only last six months.

Asked why the air force would be putting so much work into a centre for only a few months on the ground, Forget said there's a minimum standard that has to be met.

Military commanders warned before the campaign even started that degrading and defeating ISIL could take up a year -- or more.