Reuters reports: When Islamic State fighters tried to storm the Tigris River town of Dhuluiya north of Baghdad this week, they were repelled by a rare coalition of Sunni tribal fighters inside the town and Shi’ites in its sister city Balad on the opposite bank.

The assault, which began late on Tuesday and ran into Thursday, was one of several major battles in recent days in which Sunni tribes joined pro-government forces against the militants, in what Baghdad and Washington hope is a sign of increasing cooperation across sectarian lines to save the country.

Further north, another powerful Sunni tribe fought alongside Kurdish forces to drive Islamic State fighters from Rabia, a town controlling one of the main border checkpoints used by fighters pouring in from Syria.

In western Iraq, Sunni tribes have fought alongside government troops in Hit, which was captured by Islamic State fighters on Thursday, and in Haditha, site of a strategic dam on the Euphrates.

Such local alliances are still rare: in most Sunni areas of Iraq, tribes have shown little sign of turning against militants as they did when they were recruited by U.S. troops in 2006-07. Many of the leaders of that Sunni “Awakening” movement were later arrested by Baghdad, in what Sunnis see as a betrayal.

Sectarian and ethnic animosity runs deep after a decade of civil war that has touched nearly every family, making it difficult for Sunnis, Shi’ites and Kurds to trust each other.

But nearly two months into a U.S.-led bombing campaign, this week’s battles have provided the strongest early signs yet of what Washington and Baghdad hope could be a revival of the alliance with tribes to counter Islamic State. [Continue reading…]