The militias operate most actively in five major Shia cities in south-central Iraq: Kut, Hillah, Karbala, Najaf, and Diwaniyah. Kut is the hub through which people, and presumably supplies and weapons, flow from Iran into Iraq. Many of the routes from Kut run, effectively, westward or southwestward through the four other Shia cities. Militia groups, or at least their supplies, move from Kut to the other four cities.
The Shia militias apparently attempted to extend their reach beyond the four cities, into the mixed areas of northern Babil Province. In March, Shia militias evidently contested al Qaeda in the city of al Haswah, which lies at the junction of the roads north from Hillah and Karbala. Al Qaeda operatives detonated a suicide bomb at a Shia mosque in al Haswah in March. On the following day, Shia militants conducted a retaliatory bombing at an empty Sunni mosque.
Al Haswah is also connected to Kut (by way of the westward road across the Tigris at Suwayrah), and thereby to the supply route from Iran to Iraq. From al Haswah, the militias seem to have moved toward Mahmudiyah, where U.S. forces captured Iranian weapons in April.
Al Qaeda is attacking important hubs along the supply line from Iran to Iraq, in addition to the contest at al Haswah. The supply of Iranian weapons presumably follows other roads from Kut. In particular, a main road from Kut runs northwest along the Tigris to Baghdad via the towns of Aziziyah and Salman Pak. The latter has been an al Qaeda stronghold since January 2007, if not before. Al Qaeda's control of Salman Pak facilitates the organization's vehicle bomb attacks on Shia areas in eastern Baghdad. By occupying Salman Pak, al Qaeda also interdicts some of the flow of weapons from Iran to Baghdad. Al Qaeda purchased or otherwise obtained some Iranian weapons, particularly EFPs, that U.S. forces recently found in Sunni areas in southern Baghdad.
AL HASWAH HAS BEEN, therefore, a very important hub for the Shia militias as they extended their influence northward, just as Mahmoudiyah was important to al Qaeda as it extended its reach south and east. The bridge that al Qaeda destroyed on Sunday lies along the road that connects the Shia town of al Haswah with the terrain north of Mahmudiyah. By destroying the bridge, al Qaeda apparently aimed to stop the supply and northerly encroachment of Shia militias, which have increasingly threatened al Qaeda's communications from Salman Pak to Mahmoudiyah.
The recent U.S. troop increase has made it possible for Coalition and Iraqi forces to operate simultaneously all along the southern belt of Baghdad. LTG Odierno has deployed U.S. forces along the semi-circle from Yusifiyah, to Mahmudiyah, to Salman Pak (where one of the newest brigades recently began combat operations). U.S. forces are also now operating in the southern portion of Baghdad itself--in Arab Jabour and Rashid. U.S. forces have never operated aggressively in all of these areas simultaneously. As U.S. forces clear regions that al Qaeda once controlled, they take casualties from al Qaeda's fortified positions and from the Shia militia's well-placed, Iranian-supplied explosively-formed projectiles (EFPs). But their increasing effectiveness is demonstrated by the fact that al Qaeda is defending an ever-shrinking territorial position in the southern part of Baghdad and its outlying areas.
Kimberly Kagan is executive director of the Institute for the Study of War and author of The Iraq Report.