WASHINGTON — The Pentagon will consider opening more small military outposts that would provide artillery support and other aid to Iraqi forces as they prepare to retake the northern city of Mosul from Islamic State militants, a senior military officer on the Joint Staff said Wednesday.

Rear Admiral Andrew Lewis, the vice director for operations, said there may be situations where the United States would either open a base or reopen one that was used in the earlier Iraq War. Those outposts, he said, would be behind the front lines, and would be used the way US Marines are operating out of what has been known as Fire Base Bell, outside Makhmour.

Last month fewer than 200 Marines set up the outpost and provided targeting assistance and artillery fire for the Iraqis. It was the first time such a base had been established by the United States since it returned forces to Iraq in 2014.

Initially military officials said the base was set up purely to provide force protection for Iraqi forces and US advisers at the nearby Iraqi base in Makhmour.

But soon after, the Marines were firing illumination rounds to help the Iraqi forces locate Islamic State fighters and also firing artillery rounds in support of the operation, as Iraqi troops took control of several villages on the outskirts of Makhmour, southeast of Mosul. The Marines remained well behind the front lines.

Lewis said that setting up another similar base as the Iraqi forces move toward Mosul is ‘‘dependent on what’s happening on the ground’’ and in the military campaign.

‘‘As Iraqi security forces progress toward isolating Mosul, there may be a situation in which there is another base,’’ he said, adding it would be used to provide artillery fire from behind the front lines.

He added that additional security measures have been put in place at Fire Base Bell since an attack on the outpost several weeks ago.

Marine Staff Sergeant Louis F. Cardin of Temecula, Calif., was killed by rocket fire in that attack.