The Pentagon is considering plans that would place U.S. advisers closer to ground combat in Iraq and Syria in a move that could amount to a major escalation in its war against the Islamic State, a senior defense official told USA Today.

The potential move reflects growing concern at top government levels that U.S. military operations in Syria and Iraq are not making sufficient progress against the Islamic State. The official, who is familiar with the plans, was not authorized to discuss the possible changes publicly because no decisions have yet been made.

The options under consideration include placing U.S. advisers alongside local combat units in Iraq and embedding a small number of U.S. advisers with Syrian forces fighting the Islamic State, the official said.

The White House would need to approve any U.S. military expansion on the ground.President Obama has warned against expanding the U.S. role beyond its defined mission and inadvertently ushering in another Mideast war. Defense Secretary Ashton Carter said Wednesday that U.S. strategy in both countries would remain limited to supporting local forces working to defeat the Islamic State.

Last week, American Special Forces soldiers accompanied Kurdish units on a successful mission to rescue 70 prisoners from the Islamic State. A U.S. soldier, Master Sgt. Joshua Wheeler, was killed in the fighting. The Pentagon said U.S. forces would assist in future raids if conditions warranted. The U.S. military currently has about 3,400 troops in Iraq, mostly serving in an advise-and-assist mission for Iraq's military.

A U.S. Army Soldier assigned to the 1st Battalion, 32nd Infantry Regiment, 1st Brigade Combat Team, 10th Mountain Division, teaches Iraqi soldiers how to properly tie a knot, during the engineer course at the Besmaya Range Complex, Iraq, Oct. 14, 2015. The Iraqi soldiers attending the course were the first receiving training to become combat engineers. Through advise and assist and build partner capacity missions, the Combined Joint Task Force – Operation Inherent Resolve’s multinational coalition trains Iraqi security force personnel to defeat the Islamic State of Iraq and the Levant. (U.S. Army photo by Spc. Lakendra Stevens/Released)
A U.S. Army Soldier assigned to the 1st Battalion, 32nd Infantry Regiment, 1st Brigade Combat Team, 10th Mountain Division, teaches Iraqi soldiers how to properly tie a knot, during the engineer course at the Besmaya Range Complex, Iraq, Oct. 14, 2015. The Iraqi soldiers attending the course were the first receiving training to become combat engineers. Through advise and assist and build partner capacity missions, the Combined Joint Task Force – Operation Inherent Resolve’s multinational coalition trains Iraqi security force personnel to defeat the Islamic State of Iraq and the Levant. (U.S. Army photo by Spc. Lakendra Stevens/Released)

A U.S. Army soldier teaches Iraqi soldiers how to properly tie a knot on Oct. 14 during the engineer course at the Besmaya Range Complex, Iraq.

Photo Credit: Spc. Lakendra Stevens/Army

Marine Gen. Joe Dunford, chairman of the Joint Chiefs of Staff, acknowledged this week that the military is considering new options in Iraq and Syria but declined to give specifics. "We're continuing to examine ways to enhance the effectiveness of our operations," he said in testimony to the Senate Armed Services Committee.

The Pentagon hopes moving advisers closer to combat will bolster local forces' advance in the key cities of Ramadi, an influential Sunni city in western Iraq, and Raqqa, the de facto Syrian capital of the Islamic State, also known as ISIS and ISIL.

In Iraq, the military has struggled to recapture Ramadi, which fell to militants in May, but Iraqi troops have been closing in on its city center for the past week.

In Syria, Kurdish forces backed by U.S. airstrikes have had some success against the militants, but it has been largely limited to Kurdish regions in the northeast. To expand the fight beyond those regions, the U.S. recently air-dropped 50 tons of ammunition to support the Syrian Arab Coalition, a group opposed to the rule of Syrian President Bashar Assad that seeks to recapture Raqqa.

Taking back Ramadi and placing military pressure on Raqqa would be a blow to the Islamic State, which has attempted to hold territory in its attempt to create a caliphate, or state under Islamic law, across Iraq and Syria.

Staff Sgt. Adam Borjon, a 435th Construction Training Squadron engineer system’s operator, and Senior Airman Allen Turner, a 435th CTS pavement and equipment operator, build structures Sept. 23, 2015, in support of personnel recovery operations at Diyarbakir Air Base, Turkey. The 435th Contingency Response Group deployed from Ramstein Air Base, Germany, in support of the U.S. Air Forces Central Command’s staging aircraft and Airmen in southeast Turkey to enhance coalition capabilities to support personnel recovery operations in Syria and Iraq. (U.S. Air Force photo/Airman 1st Class Cory W. Bush)
Staff Sgt. Adam Borjon, a 435th Construction Training Squadron engineer system’s operator, and Senior Airman Allen Turner, a 435th CTS pavement and equipment operator, build structures Sept. 23, 2015, in support of personnel recovery operations at Diyarbakir Air Base, Turkey. The 435th Contingency Response Group deployed from Ramstein Air Base, Germany, in support of the U.S. Air Forces Central Command’s staging aircraft and Airmen in southeast Turkey to enhance coalition capabilities to support personnel recovery operations in Syria and Iraq. (U.S. Air Force photo/Airman 1st Class Cory W. Bush)

Airmen build structures Sept. 23 in support of personnel recovery operations at Diyarbakir Air Base, Turkey.

Photo Credit: Airman 1st Class Cory W. Bush/Air Force

The administration appears to be moving in the direction of engaging more directly with ground forces in Iraq and Syria, said William McRaven, a retired admiral and former commander of U.S. Special Operations Command.

"We've known for a very long time that airstrikes alone can't solve the problem," said McRaven, who is now chancellor of the University of Texas system. "You have to put boots on the ground."

"It looks like they are proceeding or moving in that direction, where Secretary Carter and the president are prepared to take more risks in ensuring that we can actively ... degrade ISIS," he said.