FOXNews Channel's Bret Bair is reporting that Pentagon officials have confirmed not only that Karbala has been isolated (as reported by Command Post earlier), but also that the 3rd Infantry Division is now driving past Karbala toward Baghdad from the southwest.

Unnamed Pentagon officials have further confirmed that the 1st Marine Expeditionary Force has crossed the Tigris west of Al Kut (as we speculated earlier) and that a fierce battle to isolate and contain Al Kut is underway right now.

The third prong of the attack is the 101st, of course, which reportedly is swinging around the west flank. Bair also noted that the 173rd along with numerous SOF and thousands of Kurds is coming down from the north, on the heels of the Republican guard units that withdrew to support Baghdad. It is unclear how close to Baghdad the "northern front" has advanced, though.

Finally, it has been noted that the Medina and Baghdad divisions have been attritted to well below 50% strength, with the implication that both divisions are near to collapse, with the other RG divisions shifting in response and support.