BBC News reports a U.S. general says Iranian-backed Shia militias in Iraq are no longer leading the operation to recapture Tikrit from Islamic State (IS) militants. Gen. Lloyd Austin, head of U.S. Central Command, said the pullback was a precondition for U.S.-led air strikes, which began on Wednesday night. Iraqi forces then launched a final push to drive IS from the city. Iraq had asked the U.S.-led coalition to mount air strikes on militants in Tikrit after the offensive stalled. Gen Austin told the U.S. Senate Armed Services Committee about 4,000 Iraqi army and federal police personnel were now carrying out "clearing operations" in Tikrit. He said the operation to retake Tikrit had stalled partly because ground forces were not being properly controlled by the Iraqi government.