U.S. commanders in Iraq have identified up to a dozen Iraqi army brigades that could mount an attack on Mosul and potentially need U.S. combat advisers at brigade-level headquarters, a top American general in Iraq said Tuesday.

Iraqi commanders and their U.S. advisers are also debating whether the primary invasion force for the Islamic State group’s stronghold should come from the Iraqi-controlled south or from the Kurdish region in the north and east — or maybe both, the general said.

The remarks from Army Maj. Gen. Richard Clarke, the head of U.S. land forces in Iraq, are the latest from top American officials that bring into focus the upcoming battle of Mosul and the role U.S. troops might play. […]