REUTERS/Youssef BoudlalBAGHDAD (AP) — Iraq's parliament speaker has expressed concern over reports of airstrikes that have allegedly killed more than 100 civilians in western Mosul where U.S.-backed government troops are fighting the Islamic State group. In tweets published on his official account, speaker Salim al-Jabouri said Saturday "we realize the huge responsibility the liberating forces shoulder" and call on them to "spare no effort to save the civilians." Al-Jabouri is a prominent Sunni Muslim politician in Iraq. It was unclear who carried out the airstrikes, but on Friday the U.S.-led coalition fighting IS in Iraq and Syria said it was investigating the allegations.