In an effort to protect the strategic Beiji oil refinery from Islamic State (ISIS/ISIL/IS) forces, the U.S. has carried out 26 airstrikes since Tuesday, according to Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff.

Dempsey also said that a mobile training team at Baghdad International Airport has been working with Iraqi forces to assist in rigging air drops.

ISIS militants have recently gained ground in the area of the refinery, which lies along the main route from Baghdad to Mosul, an area under the Islamic State control since last summer’s offensive.

The Islamic State has been using a town three miles west of the refinery, al-Seniya, as a base to reinforce fighters and supplies.

Even though the Beiji oil refinery has reportedly not operated in recent months, Dempsey said it is “geographically significant as well as significant economically,” adding that it plays a crucial role in Iraq’s petroleum infrastructure. “It’s a very important place,” he said.

“If you lose Beiji it is hard to hold Mosul,” said one U.S. military official. “If you want to move on Mosul you have to take Beiji.”

Pentagon spokesman Col. Steve Warren said Wednesday that Islamic State fighters had taken “some” of the refinery there.

The Iraqis are “under pressure there,” said Dempsey, adding that they have “lost some control of the perimeter and some of the road network,” because ISIS has been planting IEDs in the zone.

Defense Secretary Ash Carter reported Thursday that he had met with Iraqi Kurdistan Regional President Massoud Barzani and congratulated him on recapturing territory that had been lost to ISIS militants. Carter expressed his opposition to calls within Congress to work around the Iraqi government by furnishing direct aid to the Kurds and Sunni tribes.

“We oppose such a move, because we believe the unified Iraq is critical to the long-term defeat of ISIL, and because it could put some of our personnel at risk,” Carter said.

Carter also said that Pentagon analysts do not believe that the Islamic State directed Sunday’s attack on a Texas contest to draw cartoons of Muhammad, which resulted in the death of both gunmen. He did, however, suggest that the Islamic State inspires such violent behavior.

He said the attack was “yet another reason why the defeat of ISIL is important”: because of “the ability of a movement like this to inspire a certain sort of person.”

Follow Thomas D. Williams on Twitter @tdwilliamsrome.