(NewsNation) — A refueling aircraft went down in Iraq on Thursday, with a report indicating a rescue effort is underway. In a post on social media, U.S. Central Command acknowledged the refueling aircraft went down while supporting Operation Epic Fury.

The B-21 Raider is slated to become the "backbone" of the U.S. bomber force.

"The incident was not due to hostile fire or friendly fire," the release said, adding that rescue efforts are ongoing.

The event represents a precursor step toward validating capabilities essential for the B-21’s long-range, penetrating strike role.

A US Air Force KC-135 Stratotanker, a military aircraft designed to refuel other planes mid-air, crashed in western Iraq on Thursday, in an incident U.S. Central ‌Command said involved another aircraft but was not the result of hostile or friendly fire.

If you think President Donald Trump’s designs for the paint job on the new aircraft that will serve as Air Force One look familiar, you are not alone.

The KC-135 was reportedly lost after an incident involving another aircraft in friendly airspace; the second aircraft landed safely. Here’s the statement released by CENTCOM: U.S. Central Command is aware of the loss of a U.S. KC-135 refueling aircraft.

Several US Air National Guard units face uncertainty as aging F-16 fighter jets are retired with no confirmed replacement aircraft in sight.