Iraqi troops beat back Islamist insurgents in several areas north of Baghdad on Saturday, as the U.S. moved an aircraft carrier into the Persian Gulf.

A battlefield stalemate between Iraqi security forces and their militia opponents persisted into a third straight third day Saturday. Besides some minor advances by Iraq's military, it was largely quiet as Iraq's government worked to rebuild the strength of armed forces left battered and humiliated by a startling series of victories last week by a Sunni militia known as the...