Any recommendations from military commanders to send more troops to Iraq would have to receive the endorsement of Defense Secretary Chuck Hagel before going to the White House for final approval.

Asked if Hagel was open to the idea of deploying more troops, his spokesman, Rear Adm. John Kirby, said in an e-mail: “The Secretary is — and will remain — open to hearing the advice and counsel of senior military leaders. He expects that advice to be candid, forthright and forward-looking.”

Thousands of U.S. troops are stationed at bases in nearby Persian Gulf countries, from which they are carrying out a campaign of airstrikes and surveillance missions targeting the Islamic State, a group that has seized large parts of territory in Iraq and Syria.