CAMP PENDLETON, Calif. — The United States has sent 130 new military personnel to northern Iraq to review the situation in the volatile area where thousands of Iraqi civilians are trapped by fighting between Iraqi Kurds and Islamic State militants.

Secretary of Defense Chuck Hagel told a group of Marines here that the team, which arrived Tuesday in Irbil, was “not a combat-boots-on-the-ground operation” and that the American combat role in Iraq is over.

In Washington, a defense official said the team, which includes Marines and special operators, would look into ways to help thousands trapped on Mount Sinjar and prevent “potential acts of genocide” by the Islamic State. They will work closely with State Department and USAID to coordinate plans, the official said in a statement.

Hagel emphasized that the new deployment was temporary and its members will “take a closer look and give a more in-depth assessment of where we can continue to help the Iraqis with what they’re doing and the threats that they are now dealing with.”

Last week, the U.S. military began airstrikes against Islamic State fighters threatening civilians, including minority Yazidis and Christians, and to prevent the Islamic State from threatening the Iraqi Kurdish capital of Irbil where the U.S. maintains a diplomatic presence.

The U.S. and several other countries have also dropped food and water to civilians trapped on Mount Sinjar, where they fled after Islamic State fighters overran their towns and villages.

The U.S. already has 250 military advisers working with security forces in Iraq, as well as 455 U.S. security forces and 100 military personnel at the U.S. Embassy in Baghdad.

The United States has expanded its air campaign in Iraq, striking Islamic State targets near the strategic Mosul Dam for a third day Monday and using land-based bombers.

More than half of the 68 airstrikes the U.S. has conducted over Iraq since President Barack Obama authorized them Aug. 7 have been around the dam in support of Iraqi forces, according to U.S. Central Command. Fifteen of these were on Monday; 14 were on Sunday.

With the help of U.S. firepower Kurdish and Iraqi forces had largely regained control of the Mosul Dam, Iraqi officials said, cited by The Associated press. The Islamic State on Monday, however, disputed those claims.

Militants with the Islamic State group had seized the dam less than two weeks ago, pushing out Kurdish forces, known as peshmerga.

Meanwhile, a Kurdish official told the AP that the peshmerga had withdrawn from the complex because it was heavily rigged with explosives.

President Barack Obama, in a letter to Congress on Sunday, authorized the latest round of strikes, saying the order was aimed at protecting a key piece of Iraqi infrastructure and helping local fighters in their campaign to push back Islamic militants who have taken over large portions of the country. Until now, the air campaign had been focused on humanitarian aid and protecting U.S. personnel in the Kurdish regional capital, Irbil, and in Baghdad.

“These military operations will be limited in their scope and duration as necessary to support the Iraqi forces in their efforts to retake and establish control of this critical infrastructure site, as part of their ongoing campaign against the terrorist group the Islamic State of Iraq and the Levant,” Obama said.

The Mosul Dam is essential to ensuring water supplies reach populations far beyond Mosul. If Islamic State fighters destroyed the dam, large-scale flooding would likely result, potentially reaching the Iraqi capital, Baghdad.