A top official at the U.S. Department of Education resigned this week over several disputes with Education Secretary Betsy DeVos.

BuzzFeed reports that James Runcie, the former chief operating officer of Federal Student Aid, sent a letter of resignation this week that said he could no longer in good conscience perform his job if he was being asked to serve as a political pawn.

At issue was DeVos' insistence that he testify in front of the House oversight committee about improper student aid payments this week.

"I have been consistently on record and clear about not testifying at the upcoming hearing on improper payments," Runcie explained in his resignation letter.

In addition to his unwillingness to testify this week, Runcie also alleged that DeVos' education department was working to "divert critical resources" from the financial aid office.

The Trump administration's proposed budget would make some massive cuts that would eliminate college work-study programs, public-service loan forgiveness, and funding for advanced course work at public schools. Some of the savings in the budget would go toward paying for vouchers for charter schools.

One source with knowledge of the circumstances surrounding Runcie's resignation told BuzzFeed that DeVos' insistence that he testify was the "straw that broke the camel's back," as "he doesn't like being used as a political pawn."

DeVos is testifying before the House appropriations committee on Wednesday addressing other issues at the department.