(CNN) Defense Secretary Mark Esper "fired" Navy Secretary Richard Spencer for going outside of his chain of command by proposing a "secret agreement with the White House" in the case of Navy SEAL Eddie Gallagher, according to a senior defense official.

Esper on Sunday asked for Spencer's resignation after "losing trust" and "confidence in him," according to a statement from the Pentagon.

Spencer on Sunday submitted a letter to President Donald Trump that acknowledged his termination.

Read Spencer's letter below: