A small team of U.S. troops in Iraq is deployed near the front lines of intense fighting, assisting Kurdish troops calling in targets for U.S. airstrikes.

The move is part of a new aggressive push to oust Islamic State militants from the Iraqi town of Sinjar, said Defense Department spokesman Peter Cook.

Cook said the U.S. troops are not acting as joint terminal attack controllers, or JTACs, the specific military duty involving ground troops who communicate targeting locations for aircraft providing close-air support.

The American troops in Sinjar are on a hill overlooking the battlefield with binoculars, alongside Kurdish forces, providing critical intelligence that is relayed back to an operations center where military commanders are approving specific targets for airstrikes, another defense official said.

They are not technically JTACs because, the official said, JTACs normally are situated closer to the front lines, have more direct communication with pilots overhead, and bear more direct responsibility for approving targets, while the U.S. troops on Sinjar mountain are providing intelligence that is included in a broader target-approval process.

"They're not close enough to be JTACs," the defense official said.

Cook said those troops comprise one of two groups of U.S. forces involved in the Sinjar operation; the other is made up of American troops removed from the front line who are advising Kurdish commanders.

"Most of those folks, as I understand it, are behind the front lines, advising and working directly with peshmerga commanders. There are some advisers who are on Sinjar mountain, assisting in the selection of airstrike targets," Cook said.

The goal of the mission is to seize the town of Sinjar and cut off the primary Islamic State supply line between the militants group's Syrian stronghold of Raqqa and the Iraqi city of Mosul.

The mission is unusually aggressive for the 15-month-old U.S. air campaign to support Iraqis in their fight against the Islamic State group. The roughly 3,500 American troops deployed to Iraq typically remain behind the wire or far from harm's way in a train-advise-and-assist role.

But Pentagon officials recently have signaled plans to intensify the fight against Islamic State militants in Iraq and Syria. The White House for the first time authorized several dozen special operations forces troops to deploy to Syria, and Defense Secretary Ash Carter said the U.S. likely will conduct more raids like the Oct. 22 operation in Hawijah that resulted in the death of Army Master Sgt. Joshua Wheeler, the first U.S. combat death in Iraq since 2011.

Cook said there is nothing new or unique about the current mission involving U.S. troops in Sinjar, which did not require high-level Pentagon approval or any formal change in policy.

"This is part of a larger operation," he said. "We've had U.S. forces there for some time, at the secretary's approval. So my understanding is this is not something unique that required the secretary's additional approval to carry out."

The issue of whether to deploy JTACs has been a topic of intense debate among the military's top brass.

Putting troops with specialized JTAC training on the ground near enemy targets can provide valuable intelligence and improve the accuracy of airstrikes. But some military officials, as well as some high-level White House officials, are reluctant to deploy U.S. personnel that close to the fight and put them at risk of direct contact with enemy forces.

Last year, Army Gen. Lloyd Austin, the chief of U.S. Central Command, recommended deploying JTACs to improve the effectiveness of U.S. airstrikes in Iraq, but then-Joint Chiefs Chairman Army Gen. Martin Dempsey decided against putting those troops in close proximity to combat.

Putting JTACs on the ground often is cited as the logical next step in expanding the U.S. military commitment to the fight against the Islamic State group.