The current plan is to assemble about 1,000 troops, with Iraqi forces approaching Mosul from the south and Peshmerga forces from the west, said the official, who spoke on the condition of anonymity. But everything in the plan is “conditions based,” and the exact timing and size of the force to be used remains to be determined, the official said.

It’s unclear how long such an operation would take to be successful.

The idea is for groups to enter Mosul and attempt to establish initial footholds. They would then seek to expand their areas of military control, pushing out the militant terror group that also refers to itself as Islamic State, according to the official.

U.S. and coalition aircraft would provide support from the air.