(Daily Beast)Iraqi militias who once fought ISIS with U.S. help are now working with Russian and Iranian forces to crush American-backed rebels in the strategic Syrian city of Aleppo, two defense officials have told The Daily Beast.

At least three Shia militias involved in successful battles against ISIS in Iraq—the Badr Brigade, Kata’ib Hezbollah, and the League of the Righteous—have acknowledged taking casualties in fighting in south and southeast Aleppo province. U.S. defense officials confirmed to The Daily Beast that they believe “at least one” unit of the Badr Brigade is fighting in southern Aleppo alongside other Iraqi militia groups. Those groups are backed by Russian airpower and Iranian troops—and all of whom are bolstering President Bashar al-Assad’s Syrian Arab Army.

Note: Read our discussion guidelines before commenting.