WASHINGTON (AP) — Top Republican lawmakers have called on Veterans Affairs Secretary Eric Shinseki to fire his chief of staff for approving two training conferences that led to $762,000 in questionable spending.

The department had already accepted the resignation of an assistant secretary in response to a critical inspector general's report released last week. Federal investigators found the conferences were held to fulfill valid training needs, but some expenses were unnecessary or wasteful, such as $50,000 for a video that was a parody of former Gen. George S. Patton.

Rep. Jeff Miller and Sen. Richard Burr said in a letter released Tuesday that accountability begins at the top. They said the department's chief of staff, John Gingrich, bears ultimate responsibility because he approved the conferences held last year in Orlando Fla. They said in the letter that a message must be sent to all VA employees that the "perfunctory execution" of important responsibilities is inexcusable.

"To say he treated his responsibility casually is an understatement," said Miller, chairman of the House Committee on Veterans' Affairs, and Burr, the ranking republican on the Senate Committee on Veterans' Affairs. "We can only conclude that Mr. Gingrich's role was merely to provide the appearance of oversight, nothing more."

VA responded Tuesday by saying that any misuse of taxpayer dollars was unacceptable, and that's why Shinseki took action consistent with the inspector general's recommendations. The department said Gingrich's "conduct has been addressed by the secretary," but did not elaborate.

Gingrich told investigators, "I should have made sure the conferences were executed better. Now, I think people should have done more prudent work. But, it's my signature upon that page."

The inspector general recommended "appropriate administrative action" for Gingrich, but did not make specific recommendations. The report noted that Shinseki told his chief of staff that policies and procedures used to monitor conference expenses were inadequate and that he should have asked more questions.

Lawmakers and agencies are paying closer attention to employee-training conferences after a lavish conference held by the General Services Administration featured a clown, a mind-reader and a rap video.