NOBEL PEACE PRIZE UPDATE: Coalition In-Fighting Threatens the War Against ISIS in Iraq

Hostilities broke out over the weekend between two groups considered critical components of the ground war. Troops from the predominantly Shiite Muslim militias – known as the popular mobilization units or PMUs – reportedly attacked the home of an officer with the Kurdish fighting force known as the peshmerga, according to media reports. The militiamen claimed they were retaliating against an unprovoked peshmerga attack.

Fighting escalated into Sunday as peshmerga troops launched mortars and Shiite militias lit two of the Kurdish unit’s tanks on fire. Iraq’s ambassador to the U.S. described the incidents as unfortunate and in an area “where longstanding fault lines exist.”

An uneasy truce took hold Wednesday, but concern remains.

The rival forces provide the backbone to an Iraqi army that has proved less than capable in battle so far, and their continued clashes come on the eve of the U.S.-led coalition’s biggest challenge to date: the liberation of the Iraqi city of Mosul.

The right time for a swift, US-led reaction against ISIS was three years ago.